Chapter Text
Han Yoojin gasped, then rolled onto his side, retching up the sea water stuck in his lungs.
Fuck, that burned.
He flopped back, chest heaving as he sucked in life saving oxygen, eyes scrunched closed against the sun beating down on him.
“My, my. You humans are such delicate creatures.”
He whipped his head around toward the voice and yelped when he came face to face with someone much closer than he was expecting. He tried to scramble backward on weak limbs, but was caught and dragged closer instead. It wasn’t until he was pulled under the man’s body that his brain finally processed what he was looking at—because it wasn’t arms that had grabbed him.
The man had golden hair and golden eyes and perfect, pale skin. But it was below the waist where things got weird.
He had a writhing mass of golden tentacles, glistening in the sun.
Yoojin would not have been nearly as surprised if he had had a normal fish tail like he was supposed to—sirens were nothing new. He spent more time around them than most people would consider healthy. But the tentacles… was this guy part octopus? Yoojin didn’t know that sirens could be anything other than fish.
Ah, but of course even a weirdo was still goddamn beautiful.
Yoojin was embarrassingly familiar with siren good looks, as a rather plain human himself. He had raised Han Yoohyun, after all. And while Yoohyun-ie may have just barely passed for a human for many years before returning to the sea, he was the most handsome siren of all.
Hm. Though, this guy might be the second most handsome. But regardless—
“What the fuck do you think you’re doing?” Yoojin shoved against the large, bare chest pinning him down, glaring at the dazzling smile above him. The man was much larger than Yoojin too, as was typical with sirens. Fucking hell.
“Well, given that I saved your life and therefore it belongs to me now, I was examining you in order to decide what I’d like to do with you,” the siren responded, sounding awfully nonchalant for such a bold statement. The tentacle around Yoojin’s waist tightened slightly.
“Wh—that isn’t how that works! You don’t own me. At most, I owe you a favor.”
“Hmmm. I’ll consider it. Does my potential new item have a name?”
Yoojin glared, wondering if he should lie. But unlike the fae, sirens didn’t possess any particular ability to manipulate people using their names.
“Han Yoojin. And I’m not your item.”
“I’m Sung Hyunjae.”
Sung Hyunjae lifted a large hand and used it to stroke a clawed finger down Yoojin’s cheek, looking amused. Another smooth tentacle slid up under the hem of his pants, coiling around his calf.
“I didn’t ask. And stop touching.”
“How mean. Well, but I do need to be going. I’m sure we’ll meet again sometime.”
With that, he slipped off Han Yoojin and back into the glittering waves.
Huh.
Well. Yoojin was confident he was wrong—this was near Haeyeon territory, and he had never seen Sung Hyunjae before. He was confident he wouldn’t see him again.
***
“We should be getting to know each other.”
Han Yoojin sighed.
How had he ended up in this situation again? This time it was violently storming, though, which explains why the little boat he had been using got blasted by lightning. But really, what were the odds?
“I already told you, I’m not your item.”
“But I’ve saved you twice now,” Sung Hyunjae mused, once again lounging on top of Yoojin and pinning him to the sand with his much larger body. Waves crashed behind them, the water occasionally coming high enough to bathe their backs in frigid water. Neither party noticed the cold. “I believe I own you twice over.”
“You didn’t save me this time! I could have swam to land just fine. You interfered is what you did.”
“Hm. In this storm? You would’ve been crushed against the rocks over there.”
Yoojin glared up at him. That was… possible. But he wasn’t about to admit it.
“Why are you interested in me anyway? Don’t you have more important things to do than toying with a human?”
Sung Hyunjae tilted his head, golden eyes gleaming as he observed him with a clinical sort of interest.
“Are you human? I thought you were at first, but the more I observe you, the less I think so.”
“I am,” Yoojin replied firmly. Whether he was normal was a different question.
“Hmm. Well, once again, I must leave. But I do so look forward to our next encounter. Try not to drown when I’m not around to fish you out.“
And he slipped away once again, out into the heaving waves. Yoojin remained where he was for a moment, letting the water wash over him, before finally lurching upright.
***
Han Yoojin wasn’t sure why he was here.
He had had some free time that week, and for some reason he found his feet carrying him back to the secluded beach where he had now been dragged twice by that siren.
It was empty, of course. Just untouched sand glinting in the sunlight and the occasional colorful seashell or bit of seaweed. He wandered into the water just enough for it to lap at his ankles and stared out at the endless blue horizon.
He let his mind meander for a while, thinking of the chores to be done at home, the gift he wanted to get for Yerim-ie, and the preparations he’d need to get underway to spend some time at sea with the clan. Eventually, he turned around and set back out for home.
He wasn’t sure why, but he felt just the tiniest sliver of disappointment.
***
He returned the next week at the same time.
Yoohyun-ie wouldn’t be happy about it. He had asked his little brother if he knew a Sung Hyunjae while he was visiting the clan a couple days ago, and the response had been… tense, to say the least. He didn’t tell him anything useful, though, other than that he was dangerous and Yoojin should stay far, far away from him.
Yoojin had already sort of figured out both of those things. He had an innate sense for how powerful a creature's magic power was, and Sung Hyunjae’s was—Yoojin hated to admit it—even more powerful than Yoohyun-ie’s.
But nonetheless, he was a little curious about the unusual siren. And he had a suspicion that there was something he could help Yoojin with.
He wandered up to the edge of the water once again, letting the small waves swell and crest around his ankles. It was peaceful and clear again this week. Calming.
He loved the ocean. How could he not? It gave him Yoohyun-ie, after all. And the sun glittered on the waves especially beautifully today. The water seemed a more vibrant shade of blue.
After about half an hour, he turned to leave. Before he could take more than a step, he felt a slick tentacle curl around his ankle.
“I didn’t think you’d come looking for me yourself. What an obedient item I have.”
Yoojin glared over his shoulder.
“Must I repeat myself? And who says I’m here for you? It’s a beautiful day.”
Sung Hyunjae was laying in the sand only halfway out of the water, chin propped up by his hand. His hair should’ve been stuck to his head in an unflattering manner, but as with both the last times, it somehow was brushed neatly back.
Damn handsome sirens.
“Hmm. And yet, you were here last week too, but I’ve never seen you around this specific beach before I rescued you.”
“Ah, so you knew.”
“You are a peculiar human.”
Yoojin sat down in front of him. This was much more pleasant when he didn’t have a heavy body lying on top of him. He also had a clearer view of Sung Hyunjae’s lower half. A portion of the tentacles were swaying in the water, gently being pushed and pulled by the waves. They reminded Yoojin of seaweed. The other half seemed to be anchoring him to the sand and supporting his torso. All of them glimmered and shined in the sunlight.
Yoojin suddenly thought about how bright coloring on animals often was an indicator of danger. How fitting.
“Have you heard of Diarma?”
Sung Hyunjae raised both perfectly sculpted eyebrows, then threw his head back and laughed. Yoojin noticed his teeth for the first time. They were straight and white and he had canines that looked sharp enough to tear out a throat.
“Peculiar indeed. Perhaps I have. What is it you want to know?”
***
Sung Hyunjae’s information was absurdly helpful. But even more helpful was him tagging along because, as he said, it seemed like it could be fun. Yoojin was grateful for a powerful ally—especially because Yoohyun-ie would never have approved of this little adventure.
It was a complete success, even though Sung Hyunjae learned perhaps more than was safe for him to know about Yoojin’s own skills. Fortunately, the mental skill that allowed him to defeat Diarma wasn’t something that he could be privy to. Both Yoojin and Diarma seemed to pass out, and only Yoojin ever woke back up.
Diarma would no longer bother his baby brother, Yoojin had new information, and he had found two new little precious pieces of cargo that he wasn’t going to tell anyone about. Diarma’s mind had revealed how to save them and create something new, and he was excited to try. Han Yoohyun could find out when the final product hatched.
***
The following two weeks were… well. Yoojin began returning to their little beach every few days, and Sung Hyunjae would inevitably appear to greet him.
Yoojin of course didn’t say a word to Han Yoohyun about his involvement with him, as he already knew how his little brother would feel.
But after their little adventure, Yoojin realized Sung Hyunjae was a fount of both information and occasionally even useful supplies. And as a human involved with sirens, he often was in need of both. Sung Hyunjae just seemed amused by Yoojin’s requests and questions. And his tentacles did have a bad habit of wandering, but he had had to carry Yoojin quite a bit during the Diarma fiasco and so his touch no longer felt so foreign. Besides, all the powerful sirens Yoojin was close to seemed to have a habit of clinging to him. If anything, Sung Hyunjae was the most reserved about it. Yoojin was fairly certain he did it just to get a rise out of him.
But of course, he eventually found himself pinned underneath Sung Hyunjae again. He bumped a fist against his broad chest and glared up at him.
“Why am I experiencing deja vu. Get off, you’re heavy.”
“You know, I could help you with that.”
“With what?” Yoojin asked, suspiciously glaring up at him.
“The little egg in your pouch.”
“How do you know about that? And what could you possibly do?”
“I assume you know what it is you’re carrying in that bag of yours?”
“Of course. I’m taking care of it till it hatches.”
Sung Hyunjae reached down and touched the outside of the bag, head tilting.
“It will never hatch as it is at the moment. It’s cracked.”
“Cracked? It definitely isn’t. I fixed that.”
“Mmm. Whatever you did definitely helped but it’s still incomplete. And because of that, it's leaking mana. It needs more genetic material to stabilize it, and because of the delicate state it’s been in, it would benefit from a safer environment to incubate in.”
“Genetic material…? Wha—are you a pervert? What are you suggesting? Besides, if its mana is leaking, doesn’t it just need to be fed magic?”
Sung Hyunjae smirked down at him, slick tentacles curling around Yoojin’s skin.
“Well. In a way. Our magic does usually surge while mating, and that mana is part of what feeds the guppies as they grow in their eggs. But I do also mean literal genetic material. I can tell the little monster you’re taking care of is… complex. And demanding.”
Yoojin’s face heated at all the implications of what Sung Hyunjae was suggesting.
“And the safer environment? What, are you planning on taking it from me?”
Sung Hyunjae grinned, all teeth.
“Quite the opposite. I can help you become a more hospitable environment. You’re already magic-touched, which explains why the egg is willing to consider you a parent at all. With a bit more intentional magic work, you can acquire the necessary physiology to properly carry siren eggs.”
“Wait wait wait—carry? Like, I’d be pregnant?”
“I suppose you could call it that. You’re already carrying it in a pouch on your body. It’s not that different to carry it inside, is it?”
Yoojin was beet red to his hairline by now. He slapped both hands over his face and screamed a little.
“It’s completely different! How would you feel if someone suggested you change your body to carry eggs?”
Sung Hyunjae tilted his head.
“I can carry eggs. I can also fertilize them. Most sirens of solitary species can carry out both functions.”
Yoojin stared at him with wide eyes, complicated feelings fleeting across his brain as he processed this.
Huh.
Wait. Could his little brother…?
Uhm. Actually, he didn’t want to know.
“Okay… Okay. So why don’t you carry it then?”
“Are you not attached to it? Because it’s certainly attached to you. I don’t think it would accept a different host. And also, a siren needs to provide the rest of the genetic material, and I can’t do that if I’m the one carrying it.”
“Woah, time out. If you aren’t going to carry it, who says you’ll be participating at all? I can just have any siren provide genetic material, can’t I?”
Sung Hyunjae’s expression turned sharp, and Yoojin was reminded that although he had fostered some sort of weird relationship with the man above him, he was still dangerous. Yoojin was currently pinned down by one of humanity’s natural predators, having a conversation rather than being eaten. Had been spending time with him rather than being eaten.
Come to think of it. Why hadn’t Sung Hyunjae eaten him on that first day while he was still unconscious?
“Yes, you certainly could, if I allowed it.” Sung Hyunjae’s gaze turned calculating. “But your brother is Han Yoohyun, leader of the Haeyeon Clan. And I know you’ve visited him since acquiring the components of that egg from Diarma. And yet, you must have hidden it from him to both still be in possession of it and unaware of its current status.”
Ah, so he knew about all that. He had avoided bringing up his brother till now, or really explaining anything related to his involvement with sirens beyond what he was sure he revealed through his questions. And the silence on that front was mutual—Yoojin didn’t even know what clan Sung Hyunjae was a part of. But he must have been well connected, given what he knew.
The larger man leaned further into Yoojin’s space, filling his vision till he felt his breath ghosting over his lips.
“You have a reason not to tell them and likely no one else who can assist with this process. Would your beloved younger brother approve of you modifying your body to accommodate that egg? Would anyone in his clan be willing to hide such a thing from him?”
Sung Hyunjae leaned back to a less intimate distance. Yoojin could breathe again.
“I won’t help you for only part of it. If it’s to be my magic that helps shape you, then it’ll be mine that helps complete the egg as well.”
Yoojin took a moment to process.
Unfortunately, Sung Hyunjae wasn’t wrong. His beloved baby brother would never let Yoojin step outside the confines of the clan again if he ever caught wind of this plan. Or what had led to it.
“So you knew who I was the whole time. You have me at a disadvantage—Yoohyun-ie knew of you but didn’t give any details other than to stay away from you.”
“Naturally. You have heard of Seseong, I assume?”
Yoojin’s eyes narrowed at that.
“Yes. Ugh, of course that’s your clan. You all are always causing problems for my sweet younger brother.”
Sung Hyunjae laughed. As always, it was a little musical and unfairly lovely. Yoojin felt particularly insulted.
“I had heard he acts somewhat differently around his hyung, but to call him sweet… hm.”
Yoojin thumped a fist against the broad chest still hovering over him.
“He is sweet! If he’s been unfriendly it’s because you deserve it. And anyway, what do you get out of helping me?”
Sung Hyunjae smiled, golden eyes twinkling.
“You’re a fascinating creature, Han Yoojin-gun. I’ve learned quite a bit about you since our first meeting. A human that inexplicably raised a siren instead of killing it, and that ended up becoming a magic-touched as a result. Your brother went on to form one of the most powerful siren clans in the region, where you are not only welcomed, but reports say they’re all quite enamored with you—especially the strongest ones. Though, I can understand why, having spent some time with you myself.
“I’d grown rather bored, you see. And then you came along, inexplicably unafraid and even rather demanding of a mere siren such as myself. Not to mention the skills you continue to try to hide. You truly would make a rather valuable item.
“You’ve piqued my curiosity, and that is a rather powerful monster you’re growing. I have no interest in claiming the child for my clan when it hatches, but I would require that I be publicly acknowledged as a parent.”
Yoojin squinted up at him, considering.
Was this all worth it? He hadn’t exactly ever had any desire to be able to carry children himself. He was a man and happy with that—ignoring the general feelings of inadequacy when surrounded by gorgeous, muscular sirens like the one currently pinning him to the sand.
But Yoojin had truly become attached to the little egg nestled carefully in his pouch. And this would presumably be a permanent body modification, which meant he could carry other eggs in the future… and with the magical knowledge he stole from Diarma, it was possible he would have reason to want to do this again.
Also, having a permanent tie to Sung Hyunjae, even as distant co-parents, couldn’t hurt. Perhaps he could wring some more value out of him later, for the sake of their poor, dear child.
Hmm.
“You said it needs a safer environment, which you could turn me into, and that it needs genetic material, which you would provide. What order would that be happening in? How would this work?”
Sung Hyunjae cupped the side of Yoojin’s face with long, elegant fingers, thumb sliding out to run a sharp claw gently along his bottom lip.
“I mentioned intercourse makes our magic surge, yes? The most efficient method for each step would be for us to couple. Bodies tend to be more receptive to magic when they’re in a state of relaxation and pleasure as well, so if you want to change yours before the egg runs out of time, that would be the best method.”
Yoojin blinked up at him.
Ah.
“So I’d need to have sex with you twice? To change my body and to fix the egg.”
Sung Hyunjae looked amused.
“Oh, my little mate, it would be much more than that. To begin with, it’s also how the egg would be implanted. And then, it will need to be fed my mana at regular intervals until it reaches the next stage of development because your body doesn’t produce enough on its own.”
This guy… he was rather shameless, wasn’t he?
“Regular intervals? So we’d be fucking, what, weekly? And how long until the next stage?”
“Every day. Though, the more often the better for the egg—”
“WHA—“
“—And it will likely require about another two weeks, based on its current state. It was already nearing the end of this stage when you found it, it seems, which explains why it survived.”
“EVERY DAY FOR TWO WEEKS? Are you crazy? You’re fucking with me. I’m not fucking you that often for the next two weeks.”
“Hm. You could perhaps stretch it to every other day, but you’d be leaving the egg a bit starved for mana on the extra day if you did so. It will grow the healthiest and quickest with the schedule I’m suggesting. And besides, two weeks really isn’t that long, Han Yoojin-gun.”
Yoojin clapped his hands over his eyes again, groaning.
The thing is. It’s not like Sung Hyunjae was an eyesore, and Yoojin—well. He spent a lot of time with the kids. They may all be adults by now, other than Yerim-ie, but Yoojin would always be their caretaker. So spending time with Sung Hyunjae, who was distinctly older than Yoojin and felt like a fellow adult who, if anything, could take care of Yoojin, was refreshing.
Getting fucked by him could maybe be an enjoyable experience, if he was being honest with himself. The tentacles could be—uh—interesting.
It was the implications of the length of time that was the real problem. Yoojin would have to come up with some excuse for not visiting Han Yoohyun for two weeks and it would have to be a good enough reason to prevent Han Yoohyun from insisting on using his human transformation skill to accompany him. Alternatively, how would he explain bringing a rival clan member with him when he visited? And one that Han Yoohyun had explicitly told him to stay away from? Oh gods, and their need for privacy.
It’s not like he wanted to announce Sung Hyunjae was the other parent before it hatched. In fact, he had sort of hoped he could avoid the question of parentage at all costs around Yoohyun-ie.
Maybe he could just say he had stuff to take care of and meet Sung Hyunjae elsewhere? But Yoohyun-ie would almost certainly want to send Yerim-ie or one of the other high ranking sirens with him if he was going out every day during his visits.
Ugh.
He voiced these concerns to Sung Hyunjae, who shrugged, seemingly unconcerned.
“If you don’t want to outright tell the young master we’re mating, then just say I’m courting you. It will give us an excuse to see each other frequently and in private.”
Yoojin muttered the word courting, groaned again, and pointed out, “Yoohyun-ie will kill you if I tell him either of those things, especially when you dump me after two weeks and a child comes out of it eventually.”
“It’s cute that you think he could win. However, your goal was to have a child at the end of the process either way—wouldn’t it be simpler to claim it’s fully our child, rather than explain how you acquired it?”
Well—that was—Sung Hyunjae was unfortunately correct.
“…so you want to publicly claim you're courting me and that we have a child together because this entire thing will be entertaining? Because you’re bored? How does a powerful member of the most powerful clan in the region not have more interesting things to do with his time? In fact, how have you had time for any of this? You’re here all the time.”
Sung Hyunjae shrugged again, a lazy smile on his lips.
“I have everything. Power, wealth, influence. It’s rather monotonous.”
Yoojin processed that for a moment, then recalled his clan, and somehow what should’ve clicked immediately finally fell into place now.
“Fuck. Of course you do—you’re the leader.”
Yoojin groaned. He was an idiot. And he couldn’t decide if he had truly abysmal luck, or the opposite.
“No wonder my brother hates you.”
“Mm. Should I fight him for your hand? I’ve never done anything like that before.”
“Ugh. If Sung Hyunjae-ssi would like to experience something exciting, give your clan and its territories to my younger brother.”
“See? Audacious.”
Yoojin sighed. He was getting tired of being stuck to the sand like a starfish and this damn lazy cat that was lounging on him like he was the single spot of sunlight in a dark room.
“Okay. OKAY. Fine. But fuck that—I will come up with an excuse for why I’ll be gone for two weeks. I am not bringing you to Haeyeon. When can we start… reshaping me? Or whatever.”
Just as Sung Hyunjae opened his mouth to answer, Yoojin jolted, and clapped both hands over the other man’s mouth. The siren’s eyes couldn’t convey more bemusement.
“Wait a minute. What does body modification entail? I won’t lose my manhood, will I? I refuse, if that’s the case.”
Sung Hyunjae tugged the hands off his face and pinned them above Yoojin’s head with one strong hand. The other snaked down his torso and brushed against the front of his pants. Yoojin jumped at the unexpected contact.
“If you mean this, then no. If you want to get started now, I can show you exactly where things will change and how. It’ll take a few days and we’ll need to be in frequent contact, though, so I recommend making sure the young master won’t miss you. Also, is your bracelet charged enough to go underwater?”
Yoojin squirmed a little under his hands, trying to prevent the natural bodily reaction to have a gorgeous man pinning him down and touching him after they had just been discussing sex. The tentacles he had somewhat forgotten about were also suddenly jumping to the forefront of his attention, one that had been slowly swirling up his leg in particular drawing his focus.
“Ah! Uhm. Right. Uh, it’s a little low on charge. This wasn’t exactly my original plan for the day, so I wasn’t as prepared as usual. Why? Does this need to be done… underwater?”
“Being on land is rather exposing. However, if my little mate is unable to return to the sea at the moment, we can make do. There’s a cave nearby that should work.”
“Work…? Wait! I didn’t say I was ready!”
“Is the young master expecting you soon?”
“Ah, well, not exactly. I just—” Yoojin sighed. “Alright, fine, we can go. But if you plan on keeping me for several days, you’re going to need to provide food. I don’t have much on me.”
“Not a problem. What sort of mate would I be if I couldn’t provide for the one carrying my eggs?”
“Ah! Egg! Singular! Keep it straight—I am not having more children with you.”
Sung Hyunjae caressed his cheek, looking indulgent.
“Whatever you say.”
Yoojin glared and wriggled against the hands and body pinning him down again. That was a mistake—he hadn’t considered the sort of friction it would provide, and his cock was beginning to stir with curiosity now that he knew he was going to be having sex very soon.
“Are we going or what?” Yoojin grumbled, trying to direct attention away from his growing predicament. At least his clothing wasn’t soaked and sticking to him this time.
“We can go. However, there is one thing I wanted to try first, now that we’ve come to an agreement.”
Sung Hyunjae leaned down, and Yoojin was suddenly aware of every point of contact, every slippery tentacle sliding against his skin, every inch of his heavy chest pressing against Yoojin’s as he got closer, and then—the cold, salty press of his lips.
Yoojin was so startled by such a chaste kiss that it took him a moment to react. But then, Sung Hyunjae slid against his body just enough to make him gasp, and he found himself melting into it. Things quickly progressed from chaste to open mouthed kisses to tongues languidly sliding against each other.
Sung Hyunjae was like the sea—his body gently swelled forward on top of him, then ebbed back. Yoojin couldn’t help reacting, hips canting upward against him, a breathy sigh spilling from his throat.
Sung Hyunjae finally broke them apart after a minute, a string of saliva still connecting their mouths. He licked his lips.
“Shall we go?”
Yoojin just nodded, still a little dazed and surprised.
He was picked up like he weighed nothing and nestled against Sung Hyunjae’s chest, a couple of tentacles curling around him. Yoojin was once again reminded of how large Sung Hyunjae was. If he were human, he would definitely be taller than Yoohyun-ie.
They made their way back into the water and moved along the coast toward a nearby cliff face. It was pretty, with plants and sea life growing in all its rough crevices. But Yoojin didn’t see any proper caves where they came to a stop, and he looked up to find golden eyes looking back down at him.
“You’ll need to hold your breath.”
Yoojin blinked up at him, then nodded. When he was ready, they slipped under the water.
While he couldn’t stay too long under the water without the assistance of Yoo Myungwoo’s brilliant magical items, Yoojin did have an edge over an average human. He could see clearly underwater and had a decent amount of darkvision, for one. He also had a much larger lung capacity, some cold resistance, and swimming seemed to take him further faster than it should. Though of course, none of it could even begin to compare to an actual siren. To them, he was barely more sturdy in the water than a normal human.
This was why, as they made their way toward a hole in the rock face beneath the water, Sung Hyunjae kept him tucked against his body.
Yoojin didn’t really mind. It gave him the freedom to observe his surroundings, including glancing back at Sung Hyunjae’s tentacles as he swam. The gold of his tentacles glowed in sunlight, but underwater they glimmered in a way that was even more mesmerizing. It was endlessly fascinating to watch the foreign movement, the webbing between his outermost tentacles stretching taut before everything swept closed, propelling them forward. It was unfair that he did even this elegantly.
They made their way into the darkness of the tunnel, then came out the other side, breaking the still surface of the water inside of a spacious cave.
Sung Hyunjae deposited him gently on the smooth rock ledge that led into the rest of the cave, told him to wait, then ducked back into the water, leaving behind little ripples that lapped against the edge of the rock and Yoojin’s legs.
Yoojin stood up and looked around. There was the expected plant life growing along the walls, little colorful shells sticking to various corners, and what looked like moss that seemed to emit a soft glow, providing low light. It was a rather pretty cave. Though, Yoojin would’ve preferred it to have sand—sex on the stone floor would be a bit uncomfortable.
Perhaps the tentacles could act as a cushion, he mused.
He only had to wait about 20 minutes before Sung Hyunjae returned, and he spent the entire time observing the flora and fauna. He considered swimming back out to explore the area around the mouth of the tunnel, but he thought Sung Hyunjae might get on his case for not listening. Of course, this just tempted him even more, but the siren was doing him a favor here so he figured he could be generous this time.
Sung Hyunjae’s arrival was heralded by only the quiet swish of the water against the stone. However, Yoojin turned around to find him dragging a huge pile of wavy, dark green seaweed behind him. It was almost funny, until it was placed in front of him with the words, “For your nest.”
Inexplicably, he found himself flustered. Fortunately, Sung Hyunjae turned around and didn’t come back till a minute later, this time with long, familiar baskets in tow. He tied a lead to a nearby rock so they floated near the surface.
“Did you go hunting?”
“I said I would provide. I left the fish alive for now, so they’re fresh when we eat them.”
Yoojin wasn’t sure if Sung Hyunjae didn’t know that humans didn’t typically eat raw fish unless it was specially prepared for that purpose, or if he was aware that that was another thing that prolonged exposure to siren magic growing up had done to Yoojin’s body. He could consume either diet just fine. In fact—Yoojin inexplicably had a stronger stomach than even most sirens. He was completely immune to poisons.
“…thank you.”
He turned around and got to work trying to make a nest before Sung Hyunjae could get a good look at whatever his face was doing.
It wouldn't be the first time he had used a siren nest, though he had never made one for himself. He typically shared with Yoohyun-ie or Yerim-ie if he stayed the night, the latter of whom had decorated hers with shiny little trinkets and baubles. Yoojin had even gifted her some of the items lovingly threaded around the edges.
He wasn’t… entirely sure how to proceed. They were also above water, so the physics was a little different. He did his best to push it into a generally comfortable looking shape, weaving together pieces so it would hold its form, and making it wide enough so the large siren watching his work with apparent curiosity would also fit.
He stepped back when he was done, hands on his hips.
“I’ve never done this before, so please keep any unnecessary comments to yourself. And if it’s untenable, you’re welcome to rearrange it to your own incredible standards.”
Sung Hyunjae hummed.
“The best nest is one that the owner is comfortable in.”
Yoojin thought that was a surprisingly diplomatic answer. Then, he heard movement behind him, and hands and tentacles began wrapping around him, sliding over his skin and swallowing him up. Sung Hyunjae’s low voice brushed against his ear from behind.
“Shall we test it?”
Yoojin shuddered, then jerked his head, nodding.
“Humans wear so many unnecessary layers. I suppose you are delicate, though,” Sung Hyunjae mused, hand worming its way under Yoojin’s shirt, bold and sure. He tugged it off, exposing Yoojin’s chest to the cool air of the cave, before tentacles came up to take it and lay it out neatly against the rocks.
Another tentacle came up to loosen the ties on his pants, teasing against Yoojin at the same time. He jerked slightly at the careful press of teeth against the back of his neck as yet another tentacle slid across his body to assist the first in slowly tugging off his pants. Once those were laid out, both returned to strip him of his last layer, this time snaking up and into the legs of his briefs, brushing against his half hard cock as they made their way up and out, then curled around the hem to drag them down, down, down.
He felt Sung Hyunjae’s hot mouth move against his neck, a vibrant mark blooming on his pale skin as Yoojin watched the tentacles finish laying out his briefs, defenseless and exposed in the strong arms holding him in place from behind.
Sung Hyunjae slowly spun him around till they were face to face, then lifted him gently. Yoojin’s arms naturally came up to anchor around his neck. His eyes dropped once again to the siren’s pretty, pink mouth, and he realized he had no reason to hold himself back from enjoying passing whims.
As he brought their lips together, softly but demanding, Sung Hyunjae lowered them into the nest. Everything felt slick and wet—the seaweed under their bodies, their mouths moving against each other, their tongues pressing in, the tentacles snaking around his thighs, spreading him open underneath the siren.
He bucked, and a tentacle wrapped around his cock. Yoojin gasped and pulled back, panting.
“Explain. You said you would tell me what would happen.”
Sung Hyunjae wore his usual smirk as he pulled further back to give Yoojin a view of his own gently heaving body. He gave Yoojin’s cock a small tug with the tentacle still wrapped around it, pleasure pulsing from that simple gesture. Yoojin had to resist the urge to fuck further into the sensation.
“As I said—your manhood, as you referred to it, will be unaffected. In fact, there’s no reason you shouldn’t still be able to produce children. But here—” he used his hand to touch Yoojin’s perineum—“you will develop secondary sex characteristics. And you’ll be able to carry siren eggs, though not human children.”
Yoojin thought he could live with that.
“How do you even know all this? Have you done it before?”
He felt… a little weird about that, if it were the case. And a little weird for having the thought while naked and on display below Sung Hyunjae.
The little knot in his stomach quickly dissipated with his reply, though.
“No. I can’t say I’ve ever even heard of a human capable of carrying siren eggs. In your case, you’re fortunate that the young master’s magic has been slowly changing you since you were both young. As for how I know… it’s innate, I suppose. I can sense the flow of magic in your body and how my own might be able to modify and shape it.”
As he said so, he placed a hand on Yoojin’s abdomen and it began to glow. It… tingled. Before he could begin to squirm from discomfort, the tentacle on his cock started moving again, and he arched slightly, gasping. Another tentacle made its way up his chest, twisting the thin tip around a nipple, and then Sung Hyunjae leaned forward, capturing his lips in another open mouthed kiss.
So many sensations were blooming across his body, and Yoojin thought he understood what Sung Hyunjae meant about sex helping the magic. The hand on his abdomen felt warm and he found himself welcoming it as he sucked on Sung Hyunjae’s tongue.
A question slowly took shape in his mind, and he finally pulled back from the blissful warmth for a moment to ask.
“I just realized I know almost nothing about your anatomy. How does this work for you?”
A tentacle came up and wrapped around his wrist, then slowly pulled his hand into the writhing mass.
“It depends on whether I’m giving or receiving.” Yoojin’s hand was guided along the silky skin between his tentacles to what felt like a slit. He was surprised when he felt something fleshy and slick slide out of it. “This is the part you’ll be getting most closely acquainted with, though we’ll have to wait for your body to change.”
Yoojin watched Sung Hyunjae’s face carefully as he gently took what was presumably his cock in hand. Sung Hyunjae’s eyebrows furrowed and he sucked in a sharp breath. It seemed even more sensitive than a human dick. It was also shaped differently. He wasn’t sure what he was expecting, he supposed, but as he ran his fingers along it, he could feel that it was longer than that of a human, completely smooth, and it flared out at the end before coming to a pointed tip. He wondered if this was the full length or if it could extend further.
He gave an experimental stroke, and was a little shocked to see Sung Hyunjae grunt and shudder slightly above him. Somehow he was almost expecting the powerful siren to be aloof even in bed.
He licked his lips before hesitantly asking, “And… when you receive?”
Sung Hyunjae hummed, cock sliding itself up into Yoojin’s hand, before sliding it back out. He took his hand and guided it down to another slit. At first, Yoojin thought it was similar to a human vagina, but then something began to slide out as well. And it… kept coming.
“Wha—?”
A full tentacle came into view, except it wasn’t exactly a tentacle. It looked like a round series of bulbs, with ridges on the underside between each knob. It was rather… large. Sung Hyunjae guided his hand up to the somewhat bulbous tip, then pressed Yoojin’s finger to it. It…slid inside.
“That’s… Huh. Okay.”
Sung Hyunjae laughed.
“It can also remain fully sheathed and in fact generally is more pleasurable that way, but I thought you’d be interested in seeing the full thing, as it will be relevant for you in a few days. Because we have the ability to both carry and fertilize eggs, we can also transfer fertilized eggs to the more suitable partner. That is how we’ll be implanting yours, since you won’t have an ovipositor yourself.”
Ah. That was going inside Yoojin soon. The thing is—Yoojin was admittedly a bit of a hoarder when it came to information on sirens, so he was fascinated to learn all these little details, even if they were specific to whatever subspecies Sung Hyunjae was. And he had already come to terms with tentacles likely—hopefully? Fuck—entering his body, so that wasn’t surprising, despite it’s appearance.
He instead got caught on a different line of thought.
“Ah. That’s. So like. Theoretically. My dick could… go in there?”
Sung Hyunjae smirked, and the ridged tentacle slid out of Yoojin’s hand and over to his cock. As the tentacle previously wrapped around it slid off, the one Sung Hyunjae had just shown him slid on. And fuck—it was—really good.
As it split around him, his breath was knocked out of his chest by the tight, slick heat. He moaned when it slid almost all the way off, then sucked him back in.
“Hm. We can mate this way, if you’re willing.” Sung Hyunjae leaned in, licking into his mouth and adding to the wet, slick noises beginning to fill the cave.
“You know,” Yoojin murmured against his lips. “Human men also fuck each other. We just get creative.”
“Oh?” Sung Hyunjae moved to kissing down his neck, occasionally nipping him with sharp teeth.
“Mmm. Oh! Suck right there.”
Sung Hyunjae obliged, and the tingling from the hand that never left his abdomen combined with the pleasure aching in his neck, and the heat pulsing around him as Sung Hyunjae fucked himself on Yoojin’s cock. Yoojin… might be getting close already.
“Ah—right. So. We just fuck each other in the ass. Oh my gods, carefully!” Yoojin jolted as the tentacles wrapped around him lifted him just enough for another to slide between his cheeks, rubbing against his entrance. “Ah, ha. Is that…?”
It felt slicker and smoother than his other tentacles, and Yoojin realized he got his answer. Sung Hyunjae’s cock did extend fully. That was convenient.
“How careful?”
“Just—take it slow. It needs to stretch out. And normally we’d need lubricant, but your dick already has that. But don’t go sticking other tentacles in there later without prepping me first.”
Sung Hyunjae nodded, and Yoojin felt the pointed tip of his cock begin to penetrate him. It felt odd, and yet easier than it would be to take a human dick without any prep.
He relaxed into the stretch, slowly beginning to thrust up into Sung Hyunjae and then back onto his cock. Sung Hyunjae leaned down and licked a nipple, and Yoojin arched into it, little pants and grunts falling from his mouth. A tentacle slid up to tug on the other. He was—he was really enjoying the tentacles.
When the flared tip of Sung Hyunjae’s cock finally fully pushed past the tight ring of muscle, they both moaned. They breathed together for a moment, then Sung Hyunjae began thrusting in earnest, tentacles wrapping more tightly around Yoojin’s body to slide him on and off the slick cock.
The cave filled with obscene squelches and moans, both men reduced to rutting animals. Yoojin felt a little like a toy in Sung Hyunjae’s grip, unable to take any sort of control and getting used however the siren saw fit. He couldn’t say he minded—the cock pumping into him was wide and delicious and every time Sung Hyunjae forced the flared tip back out and then back in, Yoojin jolted, pleasure zipping up his spine.
“Ah, ha, ha! Sung—Sung Hyunjae-ssi! Hnnnng! Ah! I’m going to—I’m going to cum.”
Sung Hyunjae moved back up his body, licking a broad stripe up his neck before coming up to nibble on his lip.
“I’m pleased you changed your mind. Go ahead.”
Yoojin wasn’t sure what he meant by that, but he felt the tentacle tighten around his cock, and that was all he needed to spill into it, pleasure cresting from head to toe. He arched and writhed and keened, and Sung Hyunjae continued fucking him through it.
When he came back down, he pushed against Sung Hyunjae’s chest, panting.
“Give me—give me a second. The human body is very sensitive after cumming.”
All the tentacles came to a stop, and Yoojin took a moment to breathe, relaxing in Sung Hyunjae’s firm embrace.
The only place still buzzing with sensation was his abdomen. Yoojin was almost surprised that Sung Hyunjae’s hand was still there, soft glow still emanating from beneath his fingers.
Sung Hyunjae watched him quietly. Before Yoojin could start feeling awkward, he tugged him back down for a kiss. As their chests pressed together again, lips and tongues sliding against each other, he flexed upward and away from the cock in his ass, then back down, feeling the thick glide of it back in. Sung Hyunjae grunted, then began slowly thrusting into him again.
Fuck. He was definitely still sensitive. As the pace picked back up, they didn’t quite part, panting together until Sung Hyunjae hit just the right spot. Yoojin let out a noise from deep in his chest, head thrown back and back arching.
Sung Hyunjae paused, clearly surprised, then pressed back into that spot.
“Ahh! Haaa. Fuck. That’s. Too much. Ah! Sung Hyunjae-ssi! Ah-ha! Fuck!”
Yoojin wriggled, trying to get away from the cock in his ass that had started relentlessly pounding into his prostate.
“But you seem to like it? You’re hard again already,” Sung Hyunjae purred. His tentacles started moving again, two sliding up to tug on Yoojin’s nipples and two wrapping further around his thighs, keeping him spread wide for the siren’s cock. The one that had previously been sitting still around his own cock began slowly sliding upward again, then sucked him back down.
He keened.
“Do you really want me to stop, Han Yoojin-gun?” Sung Hyunjae’s low, velvety voice brushed against his ear. Yoojin felt his thick, wet cock slide out of him, every inhuman inch stretching him deliciously, then thrust back in, forcing the breath out of him. “I quite enjoyed watching you cum inside me. I’m looking forward to returning the favor.”
“Ha-ha—aaAH!”
“Hmm? Would you like that, my dear little mate?”
Yoojin was overwhelmed, pleasure pulsing from every point of contact. Every tug on his nipples, the way the tentacles on his thighs gripped him, the wet slide of the one sucking on his cock—knowing how incredibly obscene this entire display was, even without the squelches and moans dripping from his own body.
He nodded frantically.
“Fuck—yes.”
Sung Hyunjae seemed to like that. He sped up, pressed harder, sucked another mark into the skin below Yoojin’s ear. And then, Yoojin was pushed over the edge again by the feeling of the tentacle in his ass pulsing, something hot and wet spilling inside him, filling him up.
They both groaned, hands and tentacles squeezing as they came together.
It was a few moments before they loosened their grips, and Sung Hyunjae slowly slid out of him and off him, then lowered him to the nest below. He didn’t go far. The hand that had been on Yoojin’s abdomen slid around to the same spot on his back, and he tugged Yoojin against his chest, head tucked under chin.
Yoojin melted against him, sleepy from coming twice in a short period.
“Do sirens also get sleepy after sex?” Yoojin wondered out loud.
“Sometimes. I’m quite awake, however. You may sleep, I’ll watch over us.”
“Mmm. Is it working? The magic?”
“It seems so. Remaining in physical contact will keep the process going.”
“It’s… weird,” Yoojin murmured, starting to doze.
He felt a huff of laughter where his cheek was pressed against a firm pec.
“Yes, I suppose.”
As he drifted off, he felt a hand come up to stroke his hair. He couldn’t help but think that this… was actually pretty nice.