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Masturbation is supposed to be a good thing.
It provides a healthy way to explore your own body. Getting to know likes and dislikes. What gets you hard, what kills the mood. Tweaking your nipple makes your cock throb? Damn right it does. Oh, you’re not a big fan of fingers up your ass? That’s good to know.
Masturbation can be good.
It’s a damn fine stress reliever, too. The wave of endorphins washing over your body, kickstarting that feel-good sensation and even relieving some pain. Oxytocin swimming through your veins, causing you to experience more positive emotions towards the person you were thinking about during your solo fun-time. It even improves sleep quality and lowers the chance of prostate cancer in men—what's not to like?!
The sweat beading on your forehead and dripping down your temple. Wrist slapping against your thigh with every upturn, tightening and carefully twisting the tip. Trapping a nipple between your finger and thumb and rolling it between each digit.
It’s normal. It’s natural.
Katsuki doesn’t masturbate much. For a very long time, he wasn’t all that interested, anyway. He mostly avoided it because… well, exploding hands. He’s never actually given his cock any burns, but he’s never wanted to make masturbation a habit and then someday have to take a trip to Recovery Girl for her to… never mind.
Since jerking off had become a rare delicacy, Katsuki tried other methods, too. Humping his mattress only did so much. Fucking himself on a dildo was pretty good, but the prep takes so long, so he decided it would only ever become a treat. So it’s just not in his daily routine.
The thing is, Katsuki has never felt a significant urge to masturbate. As a young teenager, his head was so far up his own ass it’s a miracle he missed his own prostate. Plus, becoming the number one hero takes some serious elbow grease. He didn’t have the time to become a masturbation addict.
He only really developed the urge to masturbate since he fell in love with Izuku. It’s still not a regular occurrence, but sometimes Izuku just looks too damn fine and sometimes Katsuki is too damn hard to ignore.
The first time masturbation became a problem was during one of their sparring matches, about a week after Izuku’s 18th birthday.
Katsuki's breath comes in ragged bursts, his pulse thundering in his ears. He stands, fists clenched, glaring at Izuku, who's standing across from him in the training room, that damn smile on his face that makes Katsuki go weak in the knees.
"You ready, Kacchan?" Izuku asks, his voice steady and full of annoying, honey-sweet warmth.
"Shut up, nerd," Katsuki snaps. Eyes narrowing, Katsuki shoots forward, the air crackling with the explosive force of his quirk. He's faster than a bullet, and he's not going to let Izuku win today.
Izuku, however, dammit, always seems to know what Katsuki's going to do before he does it.
He dodges Katsuki's explosions with such fucking ease, his body moving with that fluid grace that Katsuki is secretly in awe of. It drives him crazy. Izuku is quick, calculated, always one step ahead. Katsuki aims another blast of fire and fury, but Izuku just sidesteps it like it's nothing.
"Stop dodging!" Frustration bubbles in his chest.
But Izuku moves again. Faster than before. This time, though, instead of dodging Katsuki's blasts, he closes the distance, using his quirk to launch himself towards Katsuki with a precision that takes him completely off guard. In a flash, Izuku's palm connects with Katsuki's ribcage, and Katsuki stumbles back, his vision spinning.
Before he can react, the ground shifts under him, and he's falling, falling hard onto his back. Katsuki braces himself to feel the breath knocked from his lungs, but it doesn't come.
What he feels is pressure.
Pressure on his shoulder, across his legs.
His torso is heavier.
When Katsuki opens his eyes, Izuku is pinning him down. One hand on Katsuki's shoulder, legs sprawled in a controlled manner across Katsuki's legs, straddling his torso.
His throat tightens.
He's not sure if it's the loss, or the exhaustion, or the way that Izuku is looking down at him that makes him feel so off-balance. Izuku's smile only makes it worse.
Katsuki's face flushes, hands curling into fists. "Get the fuck off me."
A giggle erupts from Izuku, leaving Katsuki’s stomach fluttering. He’s unphased by Katsuki’s threat. “You fought really well, I can barely keep up. Your physiotherapy has really been paying off.”
Blurred thoughts race around Katsuki's head as Izuku continues his rambling, all that damn praise spilling from his mouth. "You were incredible, Kacchan. Seriously, I don't know how you keep dodging me like that!"
Katsuki barely hears the words. His mind has already stopped listening, focusing on something else entirely.
Something worse.
The heat creeping up his neck.
His cheeks burning like fire.
His cock getting harder and harder in his fucking pants.
No. No, god no. Holy fucking shit. He needs Izuku to get the fuck off him before he notices.
His hands are still clenched into fists, but he can feel the tension in his body shifting. He's aware of everything. The way Izuku's voice softens as he talks, the way his green eyes sparkle with that damn glint of happiness, all that praise... and how every word that falls from his lips makes Katsuki feel like he's on fire.
"Are you okay, Kacchan?"
Katsuki's thoughts come to a grinding halt.
Blinks. He realises now he's been staring horribly at Izuku, trying to will away the boner making itself at home right under Izuku. Shit. No, no, no. He looks at Izuku briefly, but his eyes immediately dart away, landing somewhere—anywhere else. "I'm fine. Just forgot about, uh, some homework."
Katsuki knows it's a lie. Izuku knows it's a lie. Katsuki does not forget about homework. But nonetheless, Izuku heaves himself up off of Katsuki and Katsuki takes the chance to grab his gym bag and fucking bolts.
It's humiliating. Did Izuku see it?
Of course he did. Izuku never misses anything.
He gets back to his dorm room in record time, the heat pooling low in his stomach impossible to ignore. Immediately, Katsuki throws himself onto the bed and sinks one hand down below the waistband of his sweatpants. He squeezes his cock and it sends a jolt up his spine.
Steady and slow, Katsuki lies back and thinks of Izuku, palm gliding over the precum beading at the head of his cock and smearing it across the rest of the hardened flesh.
Izuku. Katsuki thinks of the way the dark green curls stuck to his forehead due to all the sweat, towering over Katsuki. He’d probably look the same during sex.
Izuku. The way he pants, completely out of breath from the workout, does Izuku look that way when he gets off?
Izuku. The whimpers he makes are exactly how Katsuki imagines Izuku sounds during sex.
Precum leaks from the head of his cock, pooling in the creases of his hand through each vigorous motion. Katsuki arches into the bed, whining Izuku’s name, squeezing the tip with every stroke.
You were incredible, Kacchan.
Heat curls in Katsuki’s stomach. It’s a telltale sign that he’s getting close—recognising the way that tension coils low in his abdomen, like a spring ready to snap. Katsuki’s hand becomes more frantic, more sweaty, he moans and cries and pants and—
Nothing happens.
Katsuki keeps stroking himself at a similar speed, the coil still tightening—
As quickly as the heat comes, it dissipates. He groans impatiently and stops touching himself for a moment, giving his wrist a break.
That’s fucking weird. Katsuki’s never had… performance issues before.
He knows it’s supposed to be difficult for women to orgasm sometimes, but to Katsuki’s knowledge, this is a rarity for men. Cocks are like, super easy to work with.
As his heart rate comes down, Katsuki’s brow furrows and he wipes his pre-soaked hand on a clean tissue from the nightstand. It wasn’t a satisfying ending by any means, but Katsuki’s putting it down to tiredness and is not overthinking it.
Human bodies are not worth overthinking about.
It happens again two months later.
Katsuki is good at English. Critical reading and comprehension is not as difficult as the rest of the dumb extras think it is. While most extras struggle with literary analysis or understanding complex sentence structures, Katsuki doesn't see the point in overcomplicating things. He knows exactly what to focus on and the clarity of the ideas being presented.
Of course, Izuku is one of the extras who struggles with English. Katsuki's not one to pretend to be bad at something just so a boy likes him, but he does offer to help tutor Izuku before their upcoming finals.
And Izuku is late to their study date.
Session.
Study session.
Izuku is late to their study session.
Whoops.
19:33. The clock seems to be slowly ticking by, and Katsuki has nearly gnawed the end of his pencil off entirely. Where the fuck is Izuku?
Has he stood Katsuki up? An uncomfortable churn in his stomach tells Katsuki that he doesn’t like that idea. Izuku wouldn’t do that to him. He must’ve just gotten held up somewhere.
And, speak of the Devil and he shall appear—when Katsuki looks up from his phone, Izuku rushes into the lounge, cheeks flushed and hair messier than usual. He's breathing a little heavy, a sheen of sweat glistening on his forehead as he wipes his face with the hem of his shirt, giving Katsuki a delicious view of his abs. The smell of fresh sweat lingers in the air as Izuku stumbles over the table, his gym bag slung over one shoulder.
And Katsuki is rock fucking hard.
Katsuki's gaze lingers for a moment too long. Eyes trail down Izuku's form—the damp, clingy t-shirt that does nothing to hide the lean muscles beneath it, the way his chest rises and falls with each breath. Katsuki's stomach tightens, the familiar flutter of arousal twisting inside him.
"Sorry I'm so late, Kacchan," Izuku stammers, finally sitting down and running a hand through his damp hair. "I lost track of time at the gym."
Heat rises to his cheeks and Katsuki grunts. "Whatever. D'ya want help or not?"
The problem is: Katsuki’s brain has now been fried. The sexy, sweaty Izuku in front of him means that the study session isn’t as smooth and casual as Katsuki was hoping, because all he can think about is his stupid fucking boner and wishing Izuku would plough him into the mattress. They finish up at their usual time, and Katsuki doesn’t waste a second darting back to his dorm room, shoving down his sweatpants, and grabbing the dildo out of his bottom drawer.
He’s not gotten round to using the dildo yet—it was an impromptu purchase after the last… technical difficulty. Katsuki knows he’s a bottom, and knows the dildo will rock his world.
Lubed fingers work their way around Katsuki’s asshole and he impatiently shoves two in without hesitation. It’s definitely weird at first, but not really uncomfortable. The taut ring gives way and reveals soft muscle inside, and when Katsuki’s fingers brush against that little bundle of nerves, his cock throbs.
It’s so much fucking better than jerking off.
He can’t let time get away from him. After scissoring himself open on a third finger, Katsuki pulls out with a sad whine, and lubes up the purple dildo that’s been eagerly sitting on the pillow watching the show.
Massaging the lube onto the dildo, Katsuki shifts his legs and gets into a better position. When he presses the tip of the silicone against his rim, he shivers—it’s big. Probably not as big as Izuku, though.
It sinks in, inch by inch, and Katsuki holds his breath patiently. Brushing against his prostate stokes a fire inside Katsuki, and he doesn’t give himself a minute to adjust, just fucking himself with abandon.
His spare hand works his cock in perfect timing, wondering if last time he just needed the extra stimulation. Tiny moans escape with every thrust, each one increasing in volume, as the sound of squelching gets louder and louder.
It doesn’t take long for Katsuki to start feeling the tension coiling in his stomach again, and a bead of sweat drips down his temple. Katsuki does not let up on that speed and rhythm—he’s been blue balled last time, he doesn’t have the patience for another round. The coil tightens and tightens and Katsuki is practically bouncing on the dildo—he worries his dorm-neighbour might hear the squeaking of the bed and the obscene squelching of the lube—but he doesn’t care. Panting, Katsuki chases that live wire in his veins, it’s so fucking close—
And it vanishes.
Katsuki groans, and not with arousal.
This is so fucking stupid, Katsuki thinks. What’s wrong with him? He’s orgasmed before. Plenty of times, thank you very much. But suddenly, now, his damn dick isn’t cooperating. He is not going to Recovery Girl about something like this—there’s probably no adult in his life he’d be willing to tell. (Read: Katsuki is an adult, but he kinda doesn’t feel like one yet).
Whatever. This problem will sort itself out in no time. It’s not like Katsuki jerks off often anyway.
Katsuki's fingers drum against the cool surface of the kitchen counter. The faint sound of clinking glass and muffled chatter from the living room filters in from the other side of the door. Impatient eyes flicker to the clock on the wall—still no sign of Izuku.
"Dammit," he mutters under his breath, more for himself than anyone else, grip tightening on the edge of the counter. It's not like Izuku to be this late.
It's Katsuki's 19th birthday, and Izuku is nowhere to be found.
Katsuki swallows the frustration, folds his arms across his chest, and tries to appear indifferent. This "surprise" party at Ponytail's place was all Izuku's idea, and he's probably still fighting some villain on patrol and is gonna turn up all bleeding and broken.
Katsuki hates parties, but he likes anything Izuku does for him.
It's just better if Izuku's actually here.
"Cheer up, Bakugou, it might never happen." Kirishima's voice cuts through Katsuki's train of thoughts.
"The fuck does that mean?"
"I—Your face—Forget it." He sighs. "What are you sulking about?"
Katsuki sees red. "I am not sulking!"
"Is it because Midoriya isn't here yet?"
"He's just running late."
"But you're upset by it."
"Oh, when did you quit hero work and retrain as a shrink?”
Kirishima laughs, but it’s fake. Forced. He opens his mouth, as if about to speak again, when the front door to Ponytail’s house (read: mansion) opens, and a familiar voice panickedly asks, “Hello? Is everyone here?”
Finally.
Katsuki's stomach does a little flip, despite himself, and he inhales sharply. He doesn't care that Kirishima is smirking in the corner at him. It's fine. Izuku's here. That's what matters.
The rest of the class gather around when Izuku stands in the doorway. His hair is disheveled, a sheepish grin plastered across his face. His eyes are wide, almost a little dazed.
Two words enter Katsuki's mind: quirk accident .
"Midoriya, what took you so long?" Asks Jirou, passing him a flute of champagne.
Izuku tilts his head, and his expression softens. "Sorry! I got hit by a quirk. It's not very major, but a villain was running around non-consensually using it on people in Shinjuku Ward." His voice is warm, almost syrupy. "But I'm here now, Sugar."
The room goes silent.
Katsuki's heart stutters for a moment before speeding up again in an unfamiliar, uncomfortable rhythm.
"What the fuck, Midoriya?" Jirou guffaws.
Mineta bursts out laughing. Uraraka is bright red. Todoroki looks confused.
"Um, sorry. It's a nickname quirk. It'll wear off in twenty-four hours." Awkwardly rubbing the back of his neck, Izuku shrugs.
Katsuki's hand tightens around his glass. His pulse is hammering now, a staccato beat he can't get under control.
"Oh!" Kaminari jumps up in excitement, which makes Katsuki roll his eyes. He can already tell where this is going. "Do me!"
Izuku's mouth twitches upward into a small smile as he steps towards Kaminari. "Spark Plug." The words spill out and almost instantly, Izuku slaps a hand over his own mouth, shocked by the words. "I'm so sorry! I don't pick them, they just come out!"
Kaminari fist-pumps the air. "Not bad!"
"Ugh." Sero rolls his eyes.
"That could've been much worse," Uraraka points out.
Izuku laughs uncomfortably, his gaze drifting towards Katsuki. It lingers for a beat too long, and Katsuki feels his throat tighten in anticipation. With a big smile that makes Katsuki's chest ache, Izuku beams and exclaims, "Happy birthday, Honey!"
Katsuki freezes.
The room collectively loses it.
"Oh my God," Ashido gasps, collapsing onto Uraraka. "Bakugou's—"
Aoyama practically falls over. "How romantic!"
Icy Hot tilts his head. "I assumed he'd end up with 'Kacchan' again."
Fuck , Katsuki's face fucking burns, and he's clenching his jaw so hard it hurts a little. "Shut the fuck up, all of you!" He growls, but it comes out weak and strangled, his voice breaking like a prepubescent teenager.
Izuku's smile drops. His eyes widen. His whole face flushes pink so fast it's almost impressive. His hand flies to the back of his neck, staring at the floor, the wall, the ceiling—anywhere but at Katsuki. "I didn't mean—Oh. Um. It’s the quirk! I just sorta—"
"This is hilarious," Kaminari chimes in.
Katsuki's heart rate is making him dizzy. Mouth dry. Body warm and uncomfortable. He had no idea that he was into pet names, and Izuku looks too fucking cute when he's nervous.
“Forget about it,” Katsuki snaps, but his voice is too shaky to have any weight. He risks a glance at Izuku—and nearly combusts on the spot when Izuku peeks at him through his fingers, wide green eyes still frantic and so, so soft.
Katsuki tries to forget about it as the party goes on. He really does try. It's not like he can ghost his own fucking birthday party, especially not one that was painstakingly labeled a "surprise" by Izuku, who looked so damn proud of himself when he saw Katsuki's lip twitch up into a sort-of smile.
But, like a typical man, Katsuki is thinking with his penis.
When he presses the beer bottle to his lips, all that can enter his mind is what it must be like to suck Izuku’s cock.
When he sees Izuku laughing with the extras, he wonders if Izuku would laugh like that during sex. Would he be comfortable enough with Katsuki to let himself go like that? Too nervous to function? A suave sex God? A bit of everything?
He nurses that damn beer bottle for two hours. Standing in corners. Letting conversations pass him by. He can't focus. Can't shake the porn in his head, clawing their way to the surface. Doesn't matter how loud the room is—his brain's louder.
He can't take it. Not the laughter, not the smug looks, definitely not the way Izuku keeps stealing glances at him with innocent eyes like he didn't just publicly detonate Katsuki's nervous system.
Okay. Fuck propriety. Katsuki has to leave.
He heads for the hallway, weaving through the crowd. Bottle dangling from his fingers, jaw tight. But the second his hand brushes the doorknob—
"Kacchan?"
That voice. That damn voice.
He stiffens. Shoulders tense as he glances back. Izuku stands just a few feet behind him, near the edge of the lounge, half-lit by string lights. And he's pulling that fucking face again. Puppy-dog eyes, worried lip-bite, hands twitching like he wants to reach out but knows he's not allowed.
(Read: he is allowed. He’s always allowed.)
Katsuki exhales through his nose. "What?"
"You're leaving?" Fuck. Izuku sounds hurt.
Katsuki doesn't answer right away. Doesn't trust himself to. He just nods.
Izuku steps closer. "But it's your birthday."
"Yeah, no shit."
"Did I... mess it up?"
Katsuki groans quietly, pinching the bridge of his nose. "You didn't—just—don't call me that again. "
"Call you what?"
"You know what."
Izuku tilts his head. "What, Honey?"
Katsuki makes a noise that can only be described as feral.
"I'm gonna kill you," Katsuki mutters, but he's already backing up, yanking the door open like it personally offended him. "I gotta get out of here before I actually kill you."
"It’s the quirk!" Izuku laughs, soft and breathy, and Katsuki hates how warm it sounds. Then, just a little quieter, just a little meaner, he says, "Goodnight, Honey."
Katsuki chokes, flips him off, and slams the door behind him.
He never expected to be the sort of guy to rush home to masturbate, but… c’mon. After that god-awful conversation, Katsuki can happily blame Izuku for this turn of events.
At home, his fist works furiously at his cock, feeling euphoric every time he pulls the foreskin over his sensitive tip. Back arching, spare hand tangled in the sheets, sweat seeping into the fabric of the bedding, mind full of Izuku.
How hard he fucking was when Izuku called him honey. How much he liked it.
Katsuki groans, lolling his head back, grip tightening on himself. His thumb ghosts over the weeping tip of his cock, slicking up the rest of his length to work it even harder. Obscene slapping sounds fill the room as Katsuki’s wrist ripples against his thigh with every downstroke.
The way Izuku went bright fucking red at Katsuki’s nervousness. Teased Katsuki to see more of his awkward spluttering. Izuku’s gotta be a menace in bed. Dirty talk whispered into Katsuki’s ear, taunting pet names that has Katsuki weak in the knees, a well-timed whimper to drag Katsuki’s orgasm from nothing.
The coil churns in his stomach, and Katsuki prepares for the disappointment, prepares for the sinking feeling of dissatisfaction. Hips bucking forward, Katsuki’s muscles tense as he chases the release. Izuku floods his mind. He tugs at the tip some more, arching his back, riding the wave—
And he cums into his hand.
The coil unravels, and white-hot pleasure floods his synapses.
"The hell?" he mutters to himself. His heart's hammering—from the workout, but maybe also from the release.
It—it makes no fucking sense.
Weeks, months, of no orgasms. And then, on his birthday of all days, he cums harder than he has in his life. He’d wonder if Izuku was the common denominator here if it weren’t for the fact that Izuku has been the material of Katsuki’s wank fantasies since he was at least fourteen years old.
A weird memory comes to mind.
“Shut up, so I can hurry up and never repeat this, ever,” Aizawa drawls, looking even more fed up than usual.
The class quietens as requested, and then Aizawa buries his face into his scarf, avoiding eye contact with literally everyone. “I don’t like getting third years at homeroom because I don’t want to talk about this, but it seems like I drew the short straw: Sex Education. Specifically, your soulmate links.”
Katsuki’s skin feels hotter. Not with rage, but with… discomfort.
He shouldn’t be listening to this. It’s not like he has a soulmate to link with.
“After you and your soulmate both turn eighteen, you will be unable to orgasm unless it’s at the same time.” Either the ceiling is really fucking interesting, or Aizawa is desperate to avoid eye contact with everyone in the room. “This counts for all forms of sexual contact, including masturbation, oral sex, and penetrative sex.”
A boyish snicker can be heard from Dunce Face & Co. Sero raises his hand and asks, “So, like, if you don’t know who your soulmate is—or worse, you do know and you’re cheating on them. If you have sex with someone else and you, uh, bust a nut, will your soulmate spontaneously… also bust a nut in their pants?”
“No,” Aizawa deadpans. “The person having sex will simply not climax. It can only happen if it’s simultaneous. Unless your soulmate is at home touching themselves at the exact same time.”
“That sounds confusing,” murmurs Frog Face.
Aizawa sighs, pinching the bridge of his nose. “There’s some evolutionary explanation for this, something about reproduction and encouraging you to only reproduce with your soulmate—the ideal match for your genes. But it has since adapted to include homosexual couples, so it can’t be entirely about reproduction anymore. I don’t know. I don’t care enough to learn about the details.”
The class unanimously frowns.
“Please remember that STDs can still be transmitted from all sorts of sexual contact, not just penetration, and you don’t wanna get signed off on sick leave from your hero agencies because you didn’t use appropriate contraception.”
“Wait,” Ponytail chimes in. “How will we know who our soulmate is? Are we expected to have multiple one-night-stand experiences?”
“Heaven forbid, no.” It’s the first time in this conversation that Aizawa has shown an iota of emotion, and this time, it’s panic and exhaustion, given the way his voice strains and almost cracks. “I don’t know or care how you figure it out, but please for the love of God, don’t just fuck around and hope to find your soulmate that way.”
Katsuki can’t bring himself to look behind him, that’d be weird. He’d probably just see the nerd scribbling down every gory detail.
Izuku probably has a soulmate. Katsuki suspects it’s Round Face. Though, maybe the nerd isn’t entirely straight, so it could be Icy Hot.
It’s not going to be Katsuki, though.
Katsuki would never have a soulmate.
He’s supposed to be alone, anyway.
“Do you have a soulmate, Sensei?”
“Class dismissed.”
Everything clicks together.
Katsuki's breath stutters, hands tightening into fists at his sides. Heartbeat pounds in his ears—it drowns out everything else.
The signs—every weird thing that's been happening—he finally sees them for what they are.
The orgasms which ghost away when he thinks of Izuku. The way his chest aches when he longs for Izuku. This time, this first time of many, that Katsuki actually cums—and it’s right after a moment intense for both of them.
Almost like…
Maybe Izuku was also—
He doesn't think. He can't. His body moves on its own. Feet slam against the floor of his apartment, as he bolts towards the front door and out into the street.
The streets are still busy at this time of night. He shoves past all the civilians, ignoring their shouts, lungs burning, legs screaming at him to slow down.
But he won't. He can't.
His head is a whirlwind of too many emotions.
Izuku. It's fucking Izuku.
It's always been him.
His soulmate.
The thought sends a shiver through him, something fierce and terrifying clawing at his ribs, eager to burst out. He rounds the last corner to Izuku's apartment, barely stopping himself from blasting straight through the door. His knuckles rap against it, too hard, too desperate.
"Izuku!"
The door swings open and Izuku is still in his attire from the party. But Katsuki’s eyes drop down to Izuku’s zipper—still open, just held together by Izuku’s hand, like it’s been open for some time and Katsuki has caught him in the act.
“Kacchan? Is everything alr—”
Katsuki’s lips are on Izuku’s in an instant. Maybe he should’ve thought more about this before risking it all, but some higher being is telling Katsuki that he’s figured it out. The kiss is just right. Izuku doesn’t even hesitate—immediately his large, powerful hands snake around Katsuki’s waist and drags him closer, kissing back in earnest. It's not rushed. It's not perfect. It's warm, a little awkward, a little trembling, like both of them are scared they'd wake up if they deepened the kiss. Izuku tastes like Asahi and devotion.
It's real.
Katsuki's hand fumbles for something solid—Izuku's shoulder, his shirt, anything to hold onto. It's dizzying.
When they pull away, barely inches apart, breath mingling, neither of them say a thing.
They don't need to.
Izuku pulls Katsuki into his apartment and slams the door behind him (with Blackwhip? With Air Force? It's far too powerful to have been done with just human strength alone).
Katsuki doesn't expect to be shoved against a wall, let alone in an act of sexual tension, let alone from Midoriya Izuku. But the thud that echoes as his back hits the wall makes his cock fucking throb.
Izuku's hand is flat against his chest, fingers splayed, strong and sure. The other grips Katsuki's hip—not rough, but firm. Grounding. Unshakable. His palms are big, warm, and suddenly everywhere, and Katsuki's brain short-circuits.
When Izuku then presses his entire body against Katsuki's, including his rock-hard veiled cock digging itself into Katsuki's thigh, he lets out a quiet, involuntary noise. Half-protest, half-surrender. It's real, it's hot and hungry and fuelled by years of no orgasms and pent-up emotion.
Izuku shifts and grinds their lengths against each other, and Katsuki bucks his hips up in return. It’s not long before Izuku desperately fumbles his hand against his zipper, freeing his cock from his pants and then doing the same for Katsuki. The first thing he notices is the cold air against the tip, added by the layer of precum oozing from the slit.
Those heavy, capable hands that Katsuki was just drooling over? Yeah, Izuku wraps one around both their lengths with ease and pumps them teasingly slowly. It stokes the fire in Katsuki’s gut, and he can’t help but whimper. The bumps and ridges on Izuku’s hands add an extra edge that Katsuki’s own soft hands miss out on, and Katsuki knows he could get used to this.
“Fuck,” Katsuki whines, throbbing hard in Izuku’s palm, which makes Izuku grip them both tighter.
Izuku gasps at the sensation, and leans forward to suck a bruise to Katsuki’s neck—he should be fucking mad about that, but his hero suit will probably hide the evidence. Katsuki is more than happy to liquidise into a pathetic puddle of love for Izuku.
Pleasure blooms behind Katsuki’s eyelids. Tears sting in his eyes, overwhelmed. His whines become more frequent, more high pitched as Izuku works their cocks so damn good, knees weakening with every growing second. The sensation of Izuku’s exhausted exhales on his sensitive skin make the hairs on his neck stand on-end.
“Izuku,” Katsuki fucking cries. Something about the patheticness of Katsuki’s whimpers must be doing something for Izuku, as a large bead of precum drips down the side of Katsuki’s cock from Izuku’s. And, in that moment, something shifts.
Izuku takes his hand away. Katsuki sobs.
“I need to see Kacchan touch himself.” Izuku sounds even more desperate now that Katsuki has been reduced into a crying, whimpering mess—his voice is breathy, dark, he licks a strip up Katsuki’s neck, enticing a shiver. “You’re so amazing. If this is—if this is real, I need to see it for myself.”
If we really are soulmates. If this hasn’t been some awful, devastating coincidence. We need to cum at the same time.
Izuku stares at Katsuki like he’s a predator and Katsuki is the prey. One hand remains on the wall by Katsuki’s head, caging him in, and it’s not something that Katsuki ever expected to get turned on by, but the new beads of pre dripping down his cock indicate that Katsuki’s learning a lot about his kinks today.
Katsuki is not someone who masturbates often. He’s never considered playing with his nipples, or fondling his balls, or teasing his foreskin. ‘Quick and efficient, get it over with’ sort of attitude. Izuku would probably enjoy a show like that, but today’s different—it’s not that he wants to get it over with, it’s that he’s so fucking horny he can’t wait a second longer.
His movements are sloppy and uncoordinated. Katsuki fucks up into his own fist harder than he thought possible, lips parted, eyelids heavy. Izuku licks his lips and watches like a starving man, stroking his own cock madly in time with Katsuki. Focusing on the head of his cock, fingers enveloped around his foreskin, Katsuki feels the way his biceps flex and his abs tense with every new movement. He feels Izuku’s eyes on him, too—sees the way his eyes practically turn into love-hearts when he sees Katsuki’s pecs bounce in perfect rhythm.
The coil in his stomach starts to tighten.
Izuku must be close, too. Eyes half-lidded, mouth parted, Izuku is debauched, but he still can’t take his gaze away from Katsuki, and it’s so fucking flattering. He knows that Izuku’s always watched him in awe, but this might just be the greatest feeling in the world. Better than beating All For One. Better than getting a second chance at life. Better than getting to do the career he loves.
Katsuki could never admit it out loud, but there's something about Izuku's eyes on him that makes him want to burn brighter, just for him.
“Are you gonna cum for me, Honey?” Izuku asks, sweet as fucking sugar, and that does it.
“Izu—”
His orgasm crashes into him in waves, and it’s relieving. So relieving, in fact, that he genuinely cries a little bit, feeling the wet droplets drip down his hot cheeks. If he wasn't mid-orgasm, Katsuki would probably feel some shame. His back arches off the wall and cum spurts over the edge of his hand and onto Izuku’s.
But his blurred eyes never leave Izuku.
And, in what might be the greatest thing that Katsuki has ever seen, Izuku cums in unison. White ropes spill over both of their hands and cocks, Katsuki’s name on his lips.
The adrenaline coursing through Katsuki’s veins wanes quickly, leaving his knees wobbling. He prepares to feel himself fall, squeezing his eyes shut in anticipation, but his knees don’t give way after all.
A distinct pressure around his waist. Warm breath against his cheek.
Izuku’s enveloped his arms around Katsuki and brought them both to the carpeted floor, and they lay down, basking in the silence and the hormones for a little while.
Katsuki’s the first one to break the silence with a tooth-bearing, boyish grin, followed by a fit of giggles. As far as birthdays go... this has been one of the better ones.
(It makes up for Izuku leaving him on his 17th birthday, but he's not going to bring that up now.)
Raising an eyebrow, Izuku glances over in awe. He can’t have heard Katsuki laugh like this often, with one of the closest times being when they fought Mr Smile. And, if Katsuki isn’t mistaken (and he sure as shit hopes he’s not), Izuku is looking at him so full of fucking love.
“I really fucking hope you’re okay with this, since the universe seems to be set on us being a thing.”
Izuku replies, at first, by shuffling closer to Katsuki and pressing a soft kiss to his dampened cheek, the smile wrinkles at the corner of his eye, his nose, and the corner of his mouth. “I was about to ask you the same. I wouldn’t mind if you wanted it to be, like, platonic, or…”
Katsuki clicks his tongue. “I don’t think it works that way, not when the soulbond involves jerkin’ it.”
“We could’ve made it work!” Izuku whines, leaning on his elbow to prop himself up and look at Katsuki. “You and I can do anything. If you didn’t like me that way, I could—”
“Like? What are you, five?”
Izuku guffaws. “What did you want me to say? If you weren’t hopelessly in love with me like I am with you? ”
The world stops.
And, then, Katsuki smiles. “Well, it’s a damn good thing that I am, then.”