Archive of Our Own

It’s been almost a month since Mark’s alien rut had hit. After William helped him out, he hasn’t had anymore of the same symptoms, but he fears the day it might happen again.

William doesn’t seem to find it awkward that they had slept together, but Mark can’t help but feel that there’s been a shift in their relationship, mostly in the way that he feels about the other man. He hadn’t really thought about William before the rut but now he can’t stop thinking about him. He’s undoubtedly attracted to William. He can’t help the way he stares. He can’t help but long for him, especially when he’s not there. He can’t help the dreams he’s been having about William.

Almost every day since his rut, he’s had some kind of erotic dream about his roommate. He’s had dreams where they sleep together again, where William sucks him off, where Mark fingers him, where Mark eats him out, where William screams his name, all traces of sass thoroughly fucked out of him. Mark, of course, feels guilty about his brain’s defilement of William, even as he strokes his cock to the idea of him more often than not. He feels insane.

They haven’t even done anything remotely sexual after the rut. In fact, William is acting as if nothing happened at all. Which is fine, except Mark isn’t sure if he should address it or just leave it be. He already thanked William for helping him out, so there’s not much else to discuss. The only thing is, he wonders if the other man would be willing to help him out again. Or if he’d be interested in fucking around even without the rut, a friends with benefits type thing. William was obviously attracted to him, judging by the way his eyes glazed over Mark’s body and the way he moaned on his cock, so maybe he would be down, but there’s no way to know for certain, which kind of freaks Mark out.

Normally, he would ask William for advice about his situation, but seeing as William is at the center of his issue, that’s not really an option. He sighs, trying to focus on an assignment. He’s been a little behind due to some superhero stuff he had to take care of last week.

William is on the other side of the room, laughing at something on his phone.

“Mark check this out” he says, walking over and shoving his phone in Mark’s face.

It’s a video with a sarcastic caption that must be funny, but Mark can’t really focus on that when William is so close. His head feels a little fuzzy at the proximity. It almost feels like when-

He forces out a laugh, “That’s hilarious” he says, praying the shake in his voice isn’t noticeable.

“Right! I gotta send this to Eve” William replies, pulling his phone away from Mark’s face and walking back over to his side of the room.

“Yeah” Mark agrees weakly, trying to turn his focus back to his assignment.

A familiar pain shoots through his gut. Not now not now, he urges the feeling to go away. William’s scent is much more potent in the air after he got close, making it hard to focus on anything else.

“I’m gonna go grab some food in the dining hall with some friends, you wanna come?” William asks, rummaging through one of his dresser drawers.

Mark doesn’t think he should go anywhere right now, “No thanks I’m good,” he says. He can feel his heartbeat in his ears, it’s too loud, too hot, too much.

“Alright, make sure you eat at some point” William says, putting his shoes on.

He’s always making sure Mark is okay. It makes Mark feel like the scum of the earth for fantasizing about him in such filthy ways.

“Okay, okay” he says, trying to play it cool until William leaves the room. He can’t burden William anymore, he decides.

William gives him a wave, “See you later” he says as he goes.

“See you,” Mark says.

As soon as the door closes Mark curls up into a ball on the bed, the low throbbing in his gut seems sharper now that William is gone. He chalks it up to his imagination at first, but the longer William is gone, the more it hurts. He’s not sure if it has to do with William specifically or if it’s just getting worse in general, but there’s no time to ruminate on that thought because what he needs now is relief, something to make the pain go away. It’s too hot and his head is throbbing.

Last time William helped him out, but this time he decides to try finding a solution alone, slipping his jeans off and reaching a hand inside his boxers to aid his aching cock. If he’s honest though, it doesn’t feel good, it actually kind of hurts, but he keeps trying. The pain only gets worse the longer he goes. Maybe he needs porn? Something to distract him from the pain so he can get off.

He begrudgingly gets up from the bed to get his phone, which he had put on the other side of the room so he could focus on his assignment, but that definitely wasn’t happening now. Getting closer to William’s side of the room is making him lightheaded, the strong scent overtaking his senses. He notices the pain in his gut lessen the closer he gets.

Does his body think it needs William or something? No, no it’s just a coincidence, he decides. He sighs, alien puberty is really confusing. William had left one of his shirts hanging on the back of his desk chair. Mark reaches out his hand without a second thought and grabs the shirt, snapping out of it when he realizes what he’s done.

With William’s shirt pressed to his face, the pain in his gut subsides. He blushes at the thought that his body seems to think that William will make him feel better, that just his scent is making him feel better.

Morals tossed aside, he grabs his phone and brings William’s shirt back to his bed. He can’t help the way he keeps the shirt close to his face, inhaling William’s scent deeply. His cock throbs in his boxers.

He squirts some lube on his hand, and this time when he reaches his hand down to stroke his cock, it doesn’t hurt, it feels amazing. He sighs into William’s shirt, closing his eyes as his brain conjures images of William. William moaning his name, William arched on the bed, William swallowing his cock down with ease.

He’s ashamed of these thoughts, yes, but it feels too good to stop now. His hand speeds up as he imagines William presenting himself to Mark, ready to be fucked.

He’s embarrassingly close already. Almost there, just a bit more-

“Will” He moans out without realizing.

All it takes to snap him out of his trance is a voice.

“Yes Mark?”

He stops dead in his tracks, hand stilling, eyes shooting open to find William standing across the room. When did he get here? How long has he been watching- how-

“You having another rut?” he asks.

Mark can’t bring himself to look up at the expression on William’s face. He must look pathetic, curled up on the bed panting into William’s shirt. He might actually die of humiliation.

“I think so,” Mark replies, voice cracking.

“Why didn’t you ask me for help?” William asks, tone laced with concern.

Mark shivers at the question, “I didn’t want to bother you and I- what if you didn’t like helping last time?” he admits quietly, still refusing to look up at the other man.

He feels a dip in the bed. “I did like helping though”.

“What-”

Before he knows it, William is laying next to him, forcing Mark to look him in the eyes.

“Let me help you,” William whispers, inching himself closer.

Mark wraps his arms around the other man, inhaling his scent.

“Mhm, you smell so good” he says quietly into William’s neck. He smells sweeter than he did during Mark’s last rut.

Mark’s hand cups William’s cheek as he brings their lips together, trying to start slow, but too pent up to do so. The kiss escalates quickly, with the two licking into each other's mouths with vigor. William shivers and ruts his hips into Mark’s. Mark can’t help the way he whines against William’s lips as they move their hips in tandem.

Pulling away from William’s lips feels impossible, so when he finally does, he moves straight to his neck. The marks he had left last time have long faded, so he opts to fix this by sucking new marks all along William’s neck.

“Ah, Mark-” William moans.

Mark pulls back to admire his work, pride overwhelming his senses. He whines as cock throbs painfully in his pants. It’s a lot harder to control himself this time around.

He buries his face in William’s neck, “Need to fuck you Will, please” he begs.

He feels William nod in agreement, so he wastes no time flipping them so he’s on top of the other man. He’s so beautiful, Mark thinks as he throws his own shirt to the side, moving to undress William as quickly as possible, struggling with the zipper on his jeans.

“Eager are we?” William asks in a teasing tone, smirking as he unzips his pants himself and removes them with ease.

Mark can’t find it in him to disagree, “yeah” he says breathlessly as he removes his own pants and boxers, his painfully hard cock springing free.

William rolls over so he’s on his stomach. “I like it this way,” he says, arching his back, probably just to tease Mark.

Make groans and his dick aches, he might’ve died and gone to heaven. William’s plump ass is on display just for him. It’s there for him to take, to claim.

“Mmm” is all Mark can get out. He roughly pulls William’s boxers down, not willing to wait any longer.

“Lube?” William asks.

“Mhm” Mark hums, too distracted by the feeling of William’s ass in his hands to process the request.

Something odd stops him in his tracks as he looks at William’s entrance.

“Feels weird” William says suddenly.

There’s some kind of liquid leaking out of William’s hole. What the-

“It wasn’t this wet last time” Mark observes dumbly.

He moves on pure instinct, slowly sticking a finger into William’s entrance.

“Ngh- Mark, wait!” William yelps.

It’s lost on Mark though, it’s so wet and warm inside he can’t think. His other hand reaches for his cock as he fucks his finger in and out of William.

“Doesn’t hurt, does it?” He asks, realizing what he’s done.

“No, it actually feels really good, add another finger,” William admits, voice shaky.

Mark does just that, adding another with ease, moving them against William’s walls, making him shiver.

“More” William asks, tone closest to begging that Mark has ever heard.

He feels tempted to tease the other man, but he simply obeys, adding a third finger. Making William moan in response. He fucks his fingers inside William with vigor, making sure to hit his prostate with each thrust.

“Ah, fuck” William whines out, pushing his ass back to meet Mark’s fingers. “Think I’m ready now” he says breathlessly.

Mark wastes no time removing his fingers, admiring the way William’s hole clenches around nothing, wet liquid running down his legs. Lube forgotten, Mark lines his cock up with William’s tight entrance.

“Did you put lube on?” William asks weakly.

“No,” he says, pushing forward slowly, sliding into William with little resistance.

“What the- ah, fuck” William wonders out loud.

Mark isn’t sure why they don’t need lube either, but he doesn’t care right now because somehow, being inside William feels even better this time. He’s so warm and tight and wet he can’t help but set a brutal pace as soon as he’s fully inside, grabbing at William’s ass to pull him closer.

“You feel so fucking good Will- it’s unreal” Mark whines out, leaning forward to suck on William’s neck.

“Mark ngh” William whimpers, “I feel weird”.

“Weird how? You okay?” Mark questions, slowing down a little, but not stopping entirely, he thinks he might die if he stops now.

William breathes shakily, “It’s kinda like you described last time. All of a sudden I’m way too hot and if you don’t keep going I feel like I’ll die” he explains. “So pick up the pace please” he almost begs.

“Okay, fuck” Mark says, starting to move his hips faster, hitting William deeper than before.

“Ah yes-” William cries out.

The wet sounds of their bodies meeting sounds obscene in the otherwise quiet room. Mark can’t take his eyes off the way his cock looks fucking into William. It’s so perfect he thinks as he squeezes the flesh of William’s ass, groaning deeply. He can feel the way that William pushes back into him as he hits his sweet spot with each thrust.

“Keep hitting right there,” William moans.

Mark does just as he’s told, continuing to pound into William’s prostate with little restraint, hopefully William doesn’t need to walk around too much tomorrow.

William keens, “Mark I’m close, so close-”

“So good Will, so good” Mark babbles back, “Please come for me Will, come on my cock”.

William whimpers, “ah”, and with that he’s spilling on the sheets, clenching around Mark so tightly that Mark feels his release coming too.

“Gonna come Will- ngh” Mark whines, finishing inside William, filling him up with hot cum.

When Mark comes down from his high, he realizes that his ‘knot’ as William had called it last time was once again expanding, stretching William out even more than he just did.

“Fuck-” he exclaims, breathing heavily, “Sorry I wasn’t planning on getting that stuck in you again I’m so sorry”. He can’t see William’s face, as he’s still on his stomach, so he’s not sure if he messed up.

“It’s okay, I don’t think anything bad will happen because of it honestly” William explains calmly.

Mark isn’t sure what something bad might be in this scenario.

“What do you mean? Could something bad happen?” He questions, a little afraid of the answer. He has kind of a bad feeling about this.

“Well, when I looked it up, it said that the purpose of a knot is to increase chances of pregnancy. But I can’t get pregnant, so it shouldn’t be a problem” William clarifies, seemingly unbothered by the matter.

Right, He can’t get pregnant.

But, what if Mark’s sperm has some kind of freaky Viltrumite powers or-

“Mark don’t worry so much, it’ll be okay,” William says calmly, “Also please stop moving around until your knot goes down”.

Mark didn’t even realize he was moving around, “Shit- sorry”.

“Just chill, okay? Everything is fine” William reassures, which really does make Mark feel better. William is right, he’s worried for no reason.

Mark lets out a sigh, “Thank you Will. I’ll chill, promise,” he replies, smile tugging at his lips.

William just laughs, “You better, you’re stressing me out”.

“Sorry I-” Mark can feel the knot retracting, “Oh, it’s going down”.

William sighs in relief, “Thank god, no offence, but I just know I’m gonna be so sore. That thing is massive”.

Mark chuckles, “Well you sure take it like a champ” he says teasingly, finally moving to pull out of William, who slumps against the bed as soon as he does.

The other man groans, “I need to sleep for like a week”.

Mark just laughs as he goes to get something to clean William up.

*

So they’ve slept together twice now, no big deal. Except it kind of is, because William said that he’s willing to help Mark out whenever his ruts hit. That simple fact makes butterflies bloom in Mark’s stomach because it means that William wants him back, even if it is just his body.

They didn't talk about it once it was over, but Mark swears there’s something in the air, something charged. They exchange glances. Mark tries not to look when William is changing, but his eyes always end up glued to the other man’s skin, silently mapping out where he wants to leave marks next time his rut hits.

William must know, there’s no way he doesn’t notice Mark’s eyes burning into him from across the room. But something tells Mark William likes the attention, he keeps coming out of the shower in the smallest towel Mark has ever seen, and he hangs around shirtless more than he ever has before. All of this can’t be a coincidence, can it? Mark feels insane trying to figure out if William is playing some game with him or if he’s just imagining things.

Another thing he isn’t sure if he’s imagining is William’s scent. It’s gotten stronger, and much sweeter ever since Mark’s last rut. He smells so fucking good Mark almost wants to ask him if he’s wearing some sort of perfume.

Sometimes he has trouble sleeping because the scent is too intoxicating, making it hard to fall asleep without jerking off in the shower quickly, thoughts of William playing in his mind. Sometimes it wakes him up in the middle of the night too, which has been fucking up his sleep schedule.

Mark jolts awake one night with the feeling that something is very wrong, the room feels way too hot and William’s sweet scent is almost suffocating, engulfing the entire room. The next thing he notices are the sounds, the creaking of the bed, panting, muffled whimpers- was William?

“Will?” Mark speaks into the room before he can stop himself.

The sounds come to a stop as he speaks, silence remains.

Mark sits up, gazing at the other man’s bed in the dark, “Are you okay?” he asks softly.

“Fuck, Mark it hurts” William groans out voice strained.

Something in Mark must be broken because despite the cry of pain, Mark feels himself getting horny. The scent in the air is making him light headed and he can feel himself getting warmer.

“What hurts Will? Can I help?” he asks shakily, trying to suppress the urge to go over there and kiss William until he can’t breathe.

“It feels like what you said your rut feels like” William offers quietly.

“What?” is all Mark can get out.

He hears William sigh breathlessly, “Fuck I don’t know, it’s too hot, I can smell you, like everywhere, and I’m so horny I might die if you don’t come over here and fuck me,” he rambles.

It’s weird that William has noticed feeling like this twice, but that’s too much to think about right now.

“Please” William whimpers.

That’s all it takes before Mark is on top of William, kissing him roughly. It’s a clash of tongue and teeth as William wraps his arms around Mark’s neck. William moans into the kiss as Mark shoves his knee in between his legs, rubbing against William’s aching cock.

“Fuck, fuck” William breathes out when they break apart.

Mark’s mouth latches onto William’s neck, licking and biting, leaving dark marks as a reminder. William’s hips buck up against Mark, desperate for any friction he can get.

William whimpers, “Mark please you have to-”

“To what Will?” Mark whispers into the other man's ear, making him shiver.

“God, just fuck me already” William breathes out, tone close to begging.

“Okay, okay” Mark replies breathlessly, grabbing hold of William’s boxers and pulling them off, leaving the other man completely exposed.

William’s boxers are wet against his fingers.

“Will, these are soaked” he says, voice laced with arousal. Something about the way William’s hole is self-lubricating is so fucking hot.

William groans in embarrassment, “I don’t know why it keeps doing that”.

“I like it” Mark replies simply, leaning down and licking a long stripe across William’s wet hole.

“Ah,” William moans out.

Call him insane but William tastes so fucking good, so sweet, warm, and wet, Mark could get addicted.

“Hey wait!” William says as Mark’s tongue prods at his entrance.

“Mmm” Mark hums, feeling that he can’t pull away, not till he’s fully tasted William.

His tongue protrudes William’s hole, deep. God he’s so lost in the taste, the feel of William clenching around him, he wants to feel him shake while he moans his name.

“Mark-” William breathes out.

Greedy to hear the sounds William makes, he pulls back and pushes a finger inside, relishing in the wet thrusting sounds and the way William’s breath catches at the intrusion. Though he can’t fully see William in the dark, he knows he looks absolutely wrecked.

“More, more” William practically cries out, which Mark takes as his sign to add another finger, then another, making quick work of opening William up for him. “Please hurry, fuck”.

It’s odd but incredibly hot to see William stripped of his sass, completely at Mark’s mercy, just from a few fingers. He needs to see this side of his roommate more often, he thinks, lining his dick up with his entrance and slowly pushing into the wet heat.

“Will, fuck” he pants out, “You feel so good”.

“Then hurry up” he complains, urging Mark to get on with it.

“Impatient today,” he chuckles, “Okay, you asked for it”.

Mark groans, slamming into William, who cries out at the sudden movement, but melts into it quickly as Mark starts to set a brutal pace.

Being inside William somehow feels better every time they fuck. This time, because his brain isn’t clouded by his rut, Mark can appreciate all the points of contact between them more fully. William’s arms wrapped around his neck, William's hands tugging at his hair, William’s legs wrapped around him tightly, it’s all so electrifying. He never wants this to end.

He can feel William clenching around him, likely approaching his orgasm.

“You close?” Mark pants out, continuing to slam into the other man’s prostate.

“Yes,” William moans out.

Mark captures William’s mouth in a wet kiss, tongue slipping into his mouth with ease. William whimpers into the kiss as he comes, hot spill pouring out onto both of their stomachs.

Mark pulls away from the kiss, allowing William a second to recover from his orgasm.

“Don’t stop, please, don't stop,” William says, breathing heavily.

“You sure?”

“Somehow, I’m still hard” William complains, Mark knows he’s rolling his eyes in the dark.

“Well we can’t have that” Mark replies, pulling out and flipping William onto his stomach, which the other man seems to like, as he moans loudly.

“Fuck-”

“You like being man handled Will?” Mark asks, voice low but teasing as he pushes back into William.

“Ah- apparently. I don’t know” William replies, embarrassment clear in his tone.

“You’re so perfect” Mark breathes out, grabbing at William’s ass as he continues to pound into him relentlessly.

William pushes his hips back against Mark, making him groan. It feels so fucking good, so wet, so warm, so tight around him. He leans down, biting at William’s neck, making him squirm.

He wraps his hand around William’s cock, pumping it in tandem with his thrusts, making the shorter man cry out.

“Mark, fuck”

“Feels good?” He asks, prideful of the moaning mess he’s made of William.

“So good it’s not even funny” William breathes out.

That primal possessive feeling he gets during his ruts rears its head as Mark smiles, riding high on the feeling that he did this to William, that he’s the only one who can do this to him, that he’s ruined William for anyone else.

He wants William to be his, and his alone, he realizes, for the first time with a clear head.

“Good, you’re doing so good Will” he pants, feeling himself getting closer and closer to the edge with each thrust.

William whimpers, “Close, close, shit,”.

“Come for me Will,” Mark groans out, pumping William faster and thrusting inside him harder.

He can feel the way William’s orgasm rips through his body, as he clenches around Mark’s length, moaning and shivering violently.

Mark fucks William through his orgasm, now chasing his own high, gripping the other man’s firm ass as he releases inside him.

“Fuck” he breathes before pulling out, not wanting to get stuck in William again.

He can hear William’s ragged breath and the way he collapses against the bed as Mark grabs a towel to clean up with, still feeling lightheaded himself.

“What the hell is going on?” William suddenly asks while Mark works to clean up their mess.

“What do you mean?”

William sighs, “Why the fuck did I feel like I was going through alien puberty just now?”

William doesn’t sound angry, just exasperated. Which is fair, this is extremely weird and Mark really has no explanation for it. Is it his fault? Maybe his cum did have some kind of fucked up powers after all.

“Will, I- I don’t know, but I’m really sorry. Does it hurt?”

“Not anymore,” William replies, rolling onto his back, probably too exhausted to think about it right now.

“I’m so sorry Will. I’ll try to figure out what’s going on, okay?” Mark says, grabbing William’s hand, trying to be comforting despite the unsettling feeling blooming in his chest.

“Okay,” is all William gets out before he’s seemingly drifting off to sleep.

Mark needs to find someone to help him out here. The last thing he wants is to destroy whatever he has with William with freaky alien stuff, even though it’s what got them into this mess in the first place.

He’s realized that his feelings for William aren’t strictly sexual, they’re romantic too. He longs to hold William, to share private moments with him, to kiss him softly instead of desperately. He wants to be with William, to treat him right, but all of this could completely fuck that up. William might never speak to him again.

He crawls into his bed after washing up, but struggles to sleep, possibilities of what might be happening playing over and over in his mind.

*

He decides that he needs to contact someone with knowledge about Viltrumines. Sadly, the only people he can think of are his father and Cecil. Considering the fact that his father is currently missing, off in space doing god knows what, Cecil is unfortunately his only option.

He swallows his embarrassment in pursuit of getting some answers for William, and meets up with Cecil at the Pentagon.

“What?” is all Cecil has to say after he explains everything that happened.

“I don’t know! My dad never said anything about this!” Mark exclaims, face feverishly red.

Cecil sighs, putting his finger against his temple in disbelief. “Look, that’s not your fault kid. But you should’ve come to us before endangering your roommate”.

Endangering? Was he hurting William after all? Fuck. His heart clenches at the thought of hurting William.

“I’m sorry-”

“Listen, Viltrumites are a species that conquers other planets, right? So to accomplish that, sometimes they have offspring with the species on other planets, much like your father did here,” Cecil begins, Mark nods. “Some species don’t have the appropriate anatomy to carry out the production of an offspring, but with enough exposure to Viltrumite semen, they can be made able to bear children”.

“What the fuck?!” Mark yelps before he can stop himself.

“So in short, you may have made male pregnancy possible. Congrats kid,” Cecil says sarcastically.

If he’s hearing this right, his cum has been fucking up William’s insides to get him ready to have a Viltrumite child. Which is inane, but it would explain why William has been affected by heat-like symptoms. But they can’t have a child, they’re only in college, and they’re not even together, how are they supposed to parent a child like that and-

“Cecil, wha- what do I do?” he asks desperately, trying to make sense of the terrifying new information.

“We can make something to suppress your ruts, and we should probably examine your roommate” Cecil says calmly, like he deals with this kind of thing everyday.

“Okay,” Mark agrees quietly, too stunned to say much else.

What is he gonna tell William? Will he be mad? What if he never speaks to Mark again? He thinks his heart might literally break in two.

“It’s going to be fine kid, just bring him in as soon as you can,” Cecil assures.

“Thanks” Mark says, head down.

*

Entering their shared dorm after learning what he just learned is terrifying, to say the least. He needs to tell William as soon as possible, but he’s so afraid that William is going to hate him.

“Hey Mark” William greets as he flies through the window, soft smile on his lips.

“Hey Will” Mark replies, not quite meeting the other man’s eye.

“Did Cecil know anything?”

He guesses he should just come out and say it.

“Um yeah,” he breathes, voice coming out shaky. After a beat, he continues, “he said that Viltrumite cum can alter other species so they can have children”.

“Oh”

“And he wants you to come in for an exam” Mark says, gaze glued to the floor, terrified of William’s reaction.

He takes William’s long silence as a sign that he’s not taking it well. “Fuck Will, I’m so sorry. I should’ve been more careful, I should’v-”

“Mark,” William’s voice cuts him off. Mark’s gaze finally shoots up to meet William’s. “It’s okay, you didn’t know,” William says comfortingly.

It’s then that Mark realizes he’s crying, hot tears streaming down his face.

“Come here,” William says, extending his arms out, beckoning Mark forward.

Mark rushes forward into William’s arms, wrapping his arms around the other man’s frame tightly, burring his face in his shoulder.

“It’s going to be okay,” William comforts, softly running his fingers through Mark’s hair.

“How are you so calm?” Mark muffles against his shoulder.

“Well, I kinda figured something like this was possible. But it felt too good to stop you during your ruts, so I just let it happen” William answers gently.

“I’m sorry Will, I shouldn’t have gotten you involved” Mark says shakily.

William pulls back from the embrace, softly guiding Mark’s face up with his hands.

Still cupping his cheek, William says, “I just said I knew this might happen. It’s as much my fault as it is yours, so let's just go get the exam and see what happens, okay?”

“Thank you Will” Mark says, tears still falling from his eyes, but now they’re tears of relief.

He’s elated, William doesn’t hate him.

Maybe everything will be okay.

*

“Mark, we’re gonna be dads!” William exclaims, walking out of the examination room Cecil’s people had taken him in.

Mark feels his heart drop. Maybe everything is not okay. He’s not against having children with William but it’s too soon, and what if it’s dangerous for William’s body and-

“Really?” Mark asks, heart beating out of his chest. “But I-”

William smirks a little, “Nah, just playing!” he says, laughing at Mark’s expression.

“Will, don’t joke like that” Mark complains as relief washes over him.

William just keeps laughing. Mark can’t say he minds though, the sound is like music to his ears.

“They said I could’ve gotten pregnant if you knotted me one more time though, so great job pulling out!” William says playfully.

“Will- not so loud” Mark replies, face burning red at the teasing even though there’s not many people around.

“Sorry bro, just complementing your pull out game” William continues shamelessly. There’s seemingly nothing William loves more than embarrassing Mark.

“God Will-”

William cuts him off, “Is it weird that I’m kinda sad I don’t get to be the Earth’s first pregnant man? I mean, I would be famous!”

“That’s not a good reason to have a child Will” Mark deadpans.

That’s seriously what William is concerned about?

“I know that, just let me dream! You’re no fun,” William pouts.

Mark decides to tease him a little, “I had no idea you dreamed about being pregnant”.

“I didn't think it was possible before” William replies, not a hint of sarcasm in his voice.

Was he serious about this? There’s no way.

“But I’ve always wanted kids, just assumed that I’d have to adopt” he continues, gazing at the wall behind Mark. “Thought it might be cool to be able to do it myself, you know?”

“Yeah,” Mark breathes out, uncertain of what else to say. How do you politely and not creepily tell your roommate with benefits that you would be more than willing to help them out with their dream? “I could uh-” Mark starts, words dying in his throat as William smirks up at him.

“What? Help me have babies? Geez why don’t you take me out on a date first” William says playfully, eyes never leaving Mark’s.

“Fine,” Mark sighs despite the smile tugging at his lips, “Would you like to go on a date with me Will?” he asks, holding his hand out to William.

“Why yes, yes I would” William replies, taking Mark’s hand and smiling at him so brightly he thinks he might melt.

“Just to confirm though, you’re not just in this for the possibility of future children, right?” Mark teases, squeezing William’s hand.

William’s innocent smile shifts into a smirk, always two steps ahead, “Well, I’m also in it for the amazing sex so-”

“Will!” Mark says, reaching his free hand to cover William’s mouth.

“What? I’m just telling the truth” William defends after pushing Mark’s hand away from his face.

“God, you’re something else Will” Mark sighs in defeat. William’s teasing always gets the best of him it seems.

William just laughs, “You love it”.

Mark smiles, “yeah, I do” he says, leaning down to kiss William slowly and softly, the way he’s been dreaming of.

William melts into the kiss, wrapping his arms around Mark. It’s everything Mark has been craving the past few weeks, it feels so right.

William pulls back after a beat.

“This isn’t a very romantic place to kiss you know,” he huffs. He always has something to complain about.

“Then let me take you on that date I promised” Mark replies.

“In this outfit?” William says, gesturing to the patient gown he was forced to wear for the testing.

Mark chuckles, “I don’t care what you wear Will, you always look good in my eyes”.

“That’s nice and all, but I need to put some pants on,” William deadpans, rolling his eyes.

Mark doesn’t miss the way his ears burn red at the compliment though, and he can’t help but smile, he loves this man so much it’s unreal.

While he’s embarrassed it took freaky alien hormones to bring them together, he wouldn’t have it any other way.