Work Text:
Izuku loves being with Kacchan.
Ever since they were kids, being with Kacchan has been like feeling the warmth of a sunspot. Sometimes, the heat became too much to bear, but he has always been the type to bask in the sun's rays rather than shy away from the heat. After their tumultuous first year at UA, they hammered away at their issues until they no longer posed a threat to the foundations of their friendship. They were practically attached at the hip throughout their second year, studying, training, and eating together more often than not.
When one of them thought of something funny, they laughed at it together hunched over their phone. They video called when they were bored, farther than one room away from each other. They visited their families together on their free weekends, making trips to the commercial center and arcade often.
There was also the touching.
Once Katsuki stopped letting his guilt and fear weigh him down, he seemed a lot more carefree, at least when it came to those he cared about. He begrudgingly let Kirishima bear hug him, Ashido poke his cheeks, and more nudging from his friends that he wouldn’t let slide before.
When it came to Izuku, he would initiate more harmless touches, almost shy in their gentleness. Brushing an eyelash away from under his eye, nudging their thighs together when they sit too close, letting his hand linger in his curls when he ruffles his hair.
They grow into more teasing touches, like a flick of his forehead or a pinch of his freckled cheek, tugging at him to get him to listen. A tickle on his ribs to make him laugh and get him out of his head. Sometimes he even initiates footsie when they sit together at lunch, to Izuku’s shock.
What started out as a head resting on a shoulder as they watch a movie turns into pinkies intertwined under blankets. After one too many nightmares and late night calls, they fell into the habit of sleeping in the same bed more often than not. More and more frequently, Izuku would wake up pillowed on Katsuki’s bicep, legs intertwined. Kacchan always complained that his arms go numb, but never fails to embrace him in the dead of the night. Even this, Izuku didn’t think to question too much in a romantic sense, just glad to seek and provide comfort in Kacchan when they needed it.
They do things this way for over a year until one day at the beginning of their third year at UA, Izuku is holding a study session with his friends in the common room. Katsuki is in his peripheral, as he almost always is these days, sitting with his friends in front of the TV. Katsuki beckons him over to where he's sitting on one of the couches, with his friends sprawled out on the floor in front of him distracted with a game.
“Oi, Deku. C’mere for a sec.”
Izuku gets up from where he was comparing notes with Shinsou, Todoroki, and Iida, huddled over their table in the corner. He plops next to Kacchan and tilts his head.
“What's up?”
Katsuki stares at him calculatingly for a long moment before grabbing his jaw and smacking a kiss on his lips. Out of nowhere.
“If it wasn’t clear, we’re dating now. Got it, nerd?” All Izuku could do was blink and nod, the brief peck enough to scramble his brain matter. He vaguely registers the snickering of Kaminari and Ashido at Katsuki’s lack of tact before he bolts to his room to freak out.
And that was that.
(Of course, later that night when they’re about to sleep all tangled up in each other in Kacchan’s bed, he asks where the kiss came from and Kacchan answers with, “You and that purple haired fucker have been real chummy lately. Gotta make sure he knows you know where home is,” he scoffs into his curls.
“Kacchan…Shinsou is dating Todoroki,” Izuku deadpans. Kacchan’s misguided concerns aside, his chest warms with the notion of Katsuki being his home. It fits all too well.
“Allegedly. Whatever, haven’t we dragged this thing out enough? We might as well call it what it is so we can get to the kissing part.”
Izuku, who honestly had no idea Kacchan felt the same way romantically, is kind of mind blown by his frankness. Then he remembers who he’s talking to. Of course he would approach dating in such a no nonsense way once he’s set his mind to it.
“You could have said something,” Izuku pouts.
“I literally just did.”
“Don't be difficult, you know what I mean,” he says, before he proceeds to smack a kiss of his own against Kacchan’s stupid, pretty mouth.)
Since then it’s been a few weeks, and it’s been really great. Really! Except, not much about their relationship has actually changed from before. Kacchan is the same snarky, vulgar, smug asshole Izuku knows and loves, and his behavior does not drift much. Not that Izuku wants him to, it would suck and honestly be a little creepy if Kacchan suddenly started acting differently. What if he was hit with a quirk? Anyway, aside from the kissing and occasional temptation of a little more than kissing, it still feels like they are two semi-codependent best friends who survived trauma together when they spend time with each other, facing their new reality one day at a time. Izuku loves it.
But he can’t help but feel a little like something is missing.
See, Izuku is a closet romantic. Growing up with his mom and watching daytime television with her for so many years seemed to infect his brain a bit. His base knowledge of romantic relationships came from daytime soaps and objectively gag-worthy romcom dramas. Thus, Izuku is unfortunately very partial to “sappy bullshit” like festival dates and sharing crepes. After a long and embarrassing night where he confessed to his mother about his relationship with Katsuki, he ended up gushing to her about how happy he was. His mom was happy to gossip with him about love and they somehow found themselves doing a bunch of love and relationship questionnaires. This is how he knows his love languages are physical touch, quality time, and words of affirmation.
He always thought that the way the couples in those shows talked to each other was always tooth-achingly sweet, with intimacy laced into every breath. It was always all I adore you sweetheart and I can’t live without you darling. He feels a little guilty for craving it, both giving and receiving that kind of sweet talk. Especially since Katsuki is a more straightforward, actions speak louder kind of guy. From what Izuku knows, he’s not the type to say meaningless pretty words for no reason, and his everyday speech hasn’t changed. Whatever the case, Izuku doesn’t think about it much, since he is the happiest he’s ever been. He’s not gonna fix what isn’t broken.
—
They’re in Katsuki's dorm, studying separately as the sun goes down and warms the room with burnt orange beams. They’re both comfy in their loungewear, with Katsuki in a worn black tank top and pair of sinful gray sweatpants that outline a certain body part that Izuku is dutifully not thinking about or looking at. In an effort to distract himself, Izuku is muttering about his hero rabbit hole of the week, perched in the center of Kacchan’s bed with his laptop out in one of Kacchan’s old oversized hoodies and his own athletic shorts. (They are admittedly a bit small on him now. He’s had these shorts since first year).
Katsuki is at his desk facing away from him, finishing up an essay when he seemingly tunes into the frequency of Izuku’s voice. He always says Izuku’s mumbling is like having the radio on at a low volume. Consistent, comforting white noise. Izuku didn’t think he was actually paying close attention, until he asks absently, “What’re you reading about, baby? Sounds interesting.”
Baby.
Immediately Izuku freezes, breath hitching and joints locking up as his face turns into molten lava. Kacchan has been so cool and stoic during the weeks they’d been dating, it felt like plus ultra best-friendship. With added benefits. He didn't really expect the way Katsuki referred to him to change when they started dating. He’s so affected he doesn't even register the question at first.
This makes Katsuki look up with a questioning noise. “Deku? Y’okay?” he asks, spinning in his desk chair to face him. He pauses as he takes in Izuku’s surely beet red complexion and his eyebrows shoot to his hairline.
“What–”
Izuku rushes to say something before Kacchan can address the reaction and mention the obvious, heart working double time in his chest.
“U-um I was reading about this newly debuted hero duo that focuses on search and rescue for natural disasters overseas?” he rambles, fidgeting with his sweater sleeve. “I thought it was so cool how they can use their quirks to adapt—“ as he rambles, he's so wrapped up in his diversion tactic he doesn't notice the smirk crawling across his boyfriend’s face.
—
He thinks he gets away with it until that night, after the sun goes down entirely and leaves behind soft moonlight, the room lit up with ambient lamplight to provide a cozy glow. They tire of studying, and Katsuki jumps up from his desk chair with a stretch before his eyes track onto Izuku like a heat-seeking missile. He prowls forward to crowd Izuku into the headboard, sitting at his hip with hands planted on either side of his waist.
“Done for the day?” Kacchan says. It’s a command disguised as a question really.
“Mhm” he responds, slamming his laptop shut and laying it on the bedside table. He can’t help that he’s eager, okay? Kacchan works him up without even trying, from his firm body and smoldering looks, his warm hands and beautiful face.
Eyes warm and mouth warmer, he drops a kiss onto Izuku's waiting pout. Izuku can’t stop himself from chasing when he leans back a bit, draping his arms around his neck and tugging. Katsuki slips his tongue across his bottom lip and sucks on it before drawing back again with a slick pop.
“You sleepin’ here tonight?” he breathes, soft voice caressing his lips like crushed velvet. It sends a tingle down to his toes, into his marrow. Izuku’s eyes flutter as Katsuki tilts his chin up in the cradle of his hand, swallowing down his harried yes that crackles with desire.
“Good,” he presses into his mouth. Izuku shudders and tugs on his blonde locks, sliding further and further down the headboard with every brush of those lips against his. He keeps remembering the timbre of Kacchan calling him baby, the way his deep gravelly voice offset the sweetness on the curl of his tongue. Just recalling it makes him quake as he drags his tongue against the roof of Katsuki’s mouth, hands roaming and hips shifting, looking for friction. Where Kacchan has a proprietary hold on his jaw and hip, tilting his head to kiss deeper into him, Izuku’s hands flit all over Kacchan’s body, feeling him up with fervency.
He tends to get a little carried away when they make out like this, but kissing Katsuki always feels so intense, like tracing livewire with his taste buds. It always escalates, because apparently Izuku is an impatient, greedy pervert when it comes to this. He doesn't really realize his, um, enthusiasm is rearing its head until Kacchan pulls back with the hand on his chin shifting his face back a bit and says with a huff, affection lining his eyes, “Slow down, baby. What's got you all hot ‘n bothered?”
Izuku’s breath hitches, this time very much detectable between the ample space of two centimeters between them. Kacchan’s eyes light up and practically dance with the realization.
“Oh? You really do like that, huh.” Sometimes, he almost forgets the way Kacchan can read him like a well worn notebook. He groans, tipping his face into Kacchan’s neck, but he just hums and ghosts his fingers over his cheek.
“Come back out here and face me like a man,” he grumbles, chest vibrating with repressed laughter.
He draws back and averts his eyes. Katsuki cups his cheeks in his hands, more like squishes them honestly, and smirks, all teeth.
“There you are. I think it's cute, really.”
“Don't tease me Kacchan,” he pouts. Katsuki gives in and bites the apple of his cheek, shifting to his full bottom lip when he whines in complaint.
“M’not teasin’, promise,” he mumbles, voice all soft and deep with the night surrounding them. He presses down on Izuku’s chest till his head rests on the pillows, elbows and forearms bracing his head with a wicked gleam in his eye.
“What is it that does it for you,” he asks, as if he doesn't know the answer already.
“I dunno,” Izuku says, picking at the side of his nails, “Makes me feel like Kacchan’s boyfriend…” he trails off, green eyes flickering around Katsuki’s head.
“Heh. You are my boyfriend, stupid.”
“Well, yeah, but—,” he sputters as Katsuki cuts him off with his lips
“Nah, I get it,” he responds, rich with want as he pushes his soft lips against Izuku’s. Katsuki hovers over his face and murmurs against his mouth, “You like when I dote on you? When I call you mine?” And Izuku’s pulse is rising so fast, heart beating a frantic rhythm that should scare him. He chokes down the whine bubbling in his throat at the words.
Lips moving against his cheek, closer and closer to his ear, “When I remind you how sweet you are, show you how precious you are to me?” He nips at his earlobe with his hand drifting to Izuku’s abdomen, rucking up his hoodie and brushing his skin lightly with his warm fingertips. Izuku can't stop himself from squirming and keening softly, his whole body alight with electricity and goosebumps.
“That’s right, you like being my baby” he rasps. Fitting his warm digits into the shallow divots between his ribs and rubbing soothingly, he hums into his ear, “My Izu-chan.”
Izuku spontaneously combusts.
The sound of his moan in the gentle quiet of the room is jarring and honestly quite pathetic. He slaps his palm over his mouth as his face burns with shameful desire and eyes feel hot with overwhelmed tears.
God.
Something about the name coming from that mouth makes him feel small and protected, which shouldn’t make sense because he can protect himself just fine, dammit. He hasn’t heard that name from those lips since they were toddlers, sticky hands melded together in the summertime heat. It makes him feel oddly cherished, knowing Kacchan remembers the cutesy way he used to call him as a child.
It also turns him on to an alarming degree, which he will not be addressing any time soon with his school sanctioned therapist.
Katsuki huffs a laugh through his nose and his lips drift down his neck, mouthing at his jumping pulse. His hands slide Izuku's palms away from his mouth.
“Don't hide from me baby” he rasps.
“K-Kacchan” he stutters, protesting and encouraging, chest thrumming like the wings of a hummingbird. He can't fight the army of butterflies wreaking havoc on his guts.
“Let me make you feel good, Izu. I wanna adore you,” he says between presses of his lips against Izuku's trembling mouth. It feels like he's going to vibrate right out of his flesh. He screws his eyes shut tight, nodding and hoping to survive the onslaught of Katsuki’s undivided attention. He feels dizzy with it.
Kacchan tugs his hoodie all the way off before he tosses it aside and drops sucking kisses all the way down to his chest. He kisses and sucks bruises along his chest, biting around his nipples before tugging them between his teeth and gently flicking his tongue. Each brush of his tongue sends a zing of pleasure straight down to Izuku’s core that makes him moan softly, his breaths short yet heavy.
“Feels good,” he whispers, running his fingers in his hair. Kacchan gives a fond hum in response, rolling his nipple between his teeth. Izuku gasps, clenching and unclenching his hands in his hair.
Once he has thoroughly given both sides the same attention, leaving his nipples tender and red, he continues down his abdomen, traveling down to his navel. He digs his tongue into his belly button, inducing a tickle that adds on to the fluttery feeling taking over his body. Izuku lets out a giggle that resembles a strange wheeze, tensing a bit with a jolt of his hip.
“Just relax. You gonna let me take care of you?” Katsuki rumbles, mirth in his mouth and affection in his eyes. The weight of his devotion threatens to push him deeper into his crevice on Katsuki's soft sheets.
“Yes, Kacchan” he breathes, heart traveling at a million miles per minute. He can’t believe how much he likes this, and obviously Katsuki knows because he snickers and blows a wet kiss below his navel before slipping his hands into the waistband of his shorts and briefs.
“Can I take these off?”
“Yes, please,”
“So polite,” he chuckles, “Keep your eyes on me, ‘kay?” he says before tugging them down, eyes tracking the way his freed erection flops onto his tummy. His head promptly dips down to kiss over it.
“Hnn!” Izuku honestly shrieks. He’d been ignoring how hard he was, already leaking at the tip from just this little bit of foreplay and words.
Katsuki tongues at him, holding his gaze as he mouths over him slowly and sensually. He drags his tongue around the tip, playing with the slit and swallowing his pre while he strokes the rest of his length with his hands. He continues teasing the head for a while, making him whine before sucking him down to the root abruptly and swiftly. He hollows his cheeks and sucks, and Izuku lets out a noise like he got punched in the gut. He wiggles his hips, panting at the suction and wet heat, until Kacchan shifts his hands to pin them down firmly, dragging his tongue along the underside on the way up as he comes up for air.
“Keep still, be good for me.” he commands, nudging back between his spread thighs. Izuku practically turns into stone in his effort to be obedient. Satisfied, Kacchan’s hand rolls around the bedside table and he snatches lube from the attached drawer. He swiftly coats his fingers, pushing his thighs over his shoulders and attaching his mouth back onto his cock.
He nudges his slick index finger against his hole, rubbing around the rim before slowly inserting it into the last knuckle as he hums around his length. Izuku throws his head back and gasps, writhing in the dampening sheets. He fights to keep from squirming too much as he curls his finger into his prostate. One finger turns into two, rubbing and gently circling the spot that makes him see sounds and hear colors. When he gets to three, he's breathless and barely holding on to his sanity as Katsuki’s tongue laves at him and head bobs in tandem with the flexing of his wrist. Eventually, he can't take it any more without feeling ready to burst. He grasps his blonde hair and tugs him, up, up, up.
“Need you, Kacchan please,” he almost doesn't recognize his own voice. Kacchan delights in his begging, eyes almost glowing as he catches his breath.
“Yeah,” he puffs out as he draws closer, seemingly magnetized to his lips, tongue curling into his mouth deep, fingers stilling in his hole. Izuku thrusts against him and back and forth on his unmoving digits for a while as they kiss sloppy before frustration crinkles his brow. Kacchan is distracted with his mouth, so Izuku takes matters into his own hands and flips them, straddling his waist with determination.
“Want it,” he gasps, rutting up and down his straining bulge, where there’s a pre-existing damp spot in the heather gray material. He pauses his gyrating as Katsuki lifts his hips to tug off his sweatpants and top. When he’s bare, and they’re skin to skin, Kacchan practically purrs, hands drifting up and around his thighs to squeeze his ass.
“You can have it, honey. Go ahead, make yourself feel good.” he breathes as he kneads his cheeks, enjoying the show. Izuku moans and feels like he’s drowning, flying, like he's on fire as he tugs at Kacchan’s rigid cock, slipping it between his cheeks making Kacchan bite down on his own swollen lip as he teases them both. He lines him up and sinks down in increments with a trembling moan, letting them both adjust. When he’s ready, his fingers curl into Kacchan’s shoulders as he drags himself up and down, moaning long and loud. He feels full to the brim with Kacchan, acclimating to the shape and curve of him.
He’s already short of breath just from this but he generates and keeps a steady pace, lifting himself up and dropping down bodily on his lap. He leans back, bracing his hands on Kacchan’s bent knees as he angles to try to press around his prostate. All the while, Kacchan’s tender hands roam up his back, caress his sweaty face, smooth down his torso to tease at his sore nipples. Like he can’t get enough of touching him. He feels like he’s gonna melt.
“Kacchan,” he begs, for what he isn't too sure. But Kacchan always answers his call, always seems to know what he needs.
“Look so pretty like this, Izu. My gorgeous little slut, take me perfectly, you were just made for me weren’t you babydoll,” he says, running his nails up and down his sides. He shifts his right hand down his abdomen, scratching lightly to make Izuku moan and tense, knowing he’s sensitive there. He smiles up at him gently before grasping his dick and circling the head with his thumb, rubbing and pressing down on the slit.
“You’re squeezin’ me so good, just like that, baby, fuck yourself on my cock.” he murmurs.
Izuku whines high in his throat, grinding down and rocking faster with the words and the stimulation. His thighs start to tremble and he’s embarrassingly close to orgasm as soon as his boyfriend opens his dirty mouth.
Katsuki notices his rhythm faltering and shifts his broad hands to a better handle on his hips.
“Need some help? My poor baby, can’t do it all on your own huh. I’ve got you, angel” he coos. Izuku flushes and bites his lip to hide his whimper. Katsuki chuckles and pecks his lips before firming his grip, hauling him up and slamming him back down hard on his cock. Izuku yelps, scrabbling for purchase and adjusting his sweaty grip back to Katsuki’s shoulders. His forearms flex with strength as he drags him effortlessly up and down his length. Izuku is making all sorts of mortifying noises as he sobs.
“Nn, ah, ah–”
He muffles himself of Kacchan’s open mouth, kissing him desperately as he starts to thrust up into him hard and deep, moaning throatily. His searing hands drift to the small of his back, pressing him tight against his abdomen as he groans against his mouth, finally losing his composure.
“Fuck, Izuku, you feel so good, wanna feel you come, want you all over me–”
And. Izuku is just a man.
Katsuki’s honeyed voice and his words, his lips moving against his, his precise thrusts, along with the friction of his muscled abdomen providing relief for his aching erection is a lethal attack combo.
“F-fuck, ah, ah, Kacchan, Kacchan” he wails as he flies so high he chokes on sweet oxygen as he shakes apart in his arms. As requested, he spills all over Katsuki, into the divots between his abs all the way up to his pillowy chest, right over his scar. He really went above and beyond obeying this one request, he thinks.
Katsuki groans and his hands dip to where they’re connected, his muscles squeezing him when his fingertips feel against his twitching hole.
“Too much,” he gasps, overstimulated as Kacchan’s hips piston faster and deeper.
“Almost there, shit—gonna come, baby, you want it inside?” he grunts, shifting his arms around Izuku's back. Izuku nods with a feeble moan, babbling, “Please, inside me, come inside—ngh.”
Katsuki embraces him tight, thrusts sloppy and erratic before he fills him up with sticky warmth with a shaky groan into Izuku’s neck, burying himself to the hilt. Izuku chokes on the heat of it, warming him up from inside out.
Kacchan peppers kisses all over the side of his face and under his eyes as Izuku trembles on the comedown.
“You're okay Izuku, you were perfect, so good for me, my pretty baby” he coos. Izuku registers the wetness underneath his eyes as tears and sniffles a bit, and wow, has he been crying this whole time? Overwhelmed, he basks in the afterglow and surrenders himself to Kacchan’s care.
—
After Kacchan cleans them both up and they both return to a regular steady heartbeat, Izuku is so embarrassed he can't bring his face out of Kacchan’s chest, where he’s lying face down in hopes of suffocating in his tits. He can at least try to bring the temperature on his cheeks down from volcanic.
He cannot believe how much a couple pet names affected his psyche. He's gonna have to get his embarrassed reactions under control if this is to continue. Suddenly, he feels Kacchan chuckle and realized at least part of that was audible. He snaps his mouth shut swiftly.
“You know, I’ve been callin’ you baby and all that other shit in my head since before we even started dating for real. If anyone should be embarrassed here, it would be me for bein’ a creep,” he deadpans.
Izuku cranes his neck up and stares. Really stares. All this time, he thought Kacchan was allergic to sappiness when in reality he is the biggest closeted simp on earth. He wishes he could peer into his mind for a day to really fathom how his brain works.
“Well, you saw how I reacted when you first called me…b-baby. I thought you were just trying to make me blush because you know I like things like that,” he mumbles.
“Nah it just slipped out today. Your reactions were an unexpected bonus, heh. Anyway, I like when you get all flustered and shit. Makes me wanna tease you and spoil you rotten, also makes my teeth ache to bite you,” he says, fingers trailing up and down his nape.
“Kacchan has a biting problem. Do we need to get you a teething toy?” He can only address one part of that sentence without dying.
“Shut the fuck up.” To emphasize his point, he brings Izuku’s fingers up from where they are resting, undisturbed, and chomps on them like an animal.
“Ow! You foul beast, bad Kacchan!” he says, ignoring the inopportune flare of heat that just went down his spine. He’s not ready for Kacchan to exploit his reaction to this particular interest quite so soon.
Kacchan growls at him like a dog with a toy. It’s unfortunately hot.
Giggling, he spaces out a bit, pecking absently at the scar tissue above his heart. Izuku peeks up into his gorgeous red eyes, seeing the love barely hidden there with gemstone clarity and realizes he is not missing out on anything. Like Kacchan said, he has been spoiling him with his affection in many ways since before they got together. The way he cooks for them, reminds him of what’s important when his brain gets too scattered to hold in information, wipes his tears away when he cries away but doesn't dismiss his feelings.
The way he always gives Izuku the bed and sits at his desk so Izuku has more room to spread his notes when they study together. The soft tone of his voice when the two of them are together. The way he squeezes and massages his hands when they ache, and becomes his weighted blanket, pressing his body down with his own when he trembles with anxiety after nightmares. His gentle hands when guiding his joints through their daily stretches. The fact that he actually, literally died and came back, all for him. Honestly, there’s not much room for doubt. Kacchan loves him, just as deeply as he loves Kacchan.
He comes back to himself, mouth to his chest. “You know, you already spoil me. I guess it just took me getting smacked in the face with your sappiness while horny to embrace it fully,” he says blithely.
Kacchan snorts and squeezes him tighter, cheek squishing against the top of his head
“Yeah, well. I've got a bleeding heart, sue me.”
It's a testament to their growth that Izuku doesn't start bawling at the off color joke. To be fair, the sex endorphins leave little room for sadness. Still, he mutters, “Not funny” indignantly against the scar on his chest.
“Okay, baby,” he smiles into his hair.
(He doesn’t say sorry anymore. Many of their arguments have been about their guilt and their regrets, but Katsuki’s sacrifice has never been one of his own regrets. He wears his scars with honor, a mark of how far his love and protection will go for Deku. The only thing he was sorry for when he returned to Deku’s side was the hurt he put him through when he left him behind.
A funny thought dissipates any gloominess in his head. He really does love teasing Deku until he’s pink in the face. He’s so adorable.)
“So when are you gonna start calling me da-”
Izuku smacks the pillow over his mouth and squeaks.
“KACCHAN!”
Katsuki, probably expecting this reaction, cackles underneath him and pleads “Darling! I was gonna say darling, Deku, how deep in the gutter is your mind, huh,” he smirks, the smug bastard.
“Stop making fun of me! I just like when you call me cute names, I don't have a d-daddy kink,” he pouts, whispering the last part under his breath. He can’t even say it without feeling an embarrassed shiver down his spine.
“We’ll see about that…” he teases with a naughty smirk.
“Shut up and sleep, stupid.”
“Hey, who’s stupid.”
“Kacchan is”
“If I’m stupid, then you’re an idiot,” Katsuki huffs and rolls them deeper into the bedding, smothering Izuku completely as he grumbles almost inaudibly “And I like it when you call me Kacchan.”
“Huh?”
“Nothin’. I’m asleep.”
Izuku smiles to himself as he drifts off.
They have all the time in the world to discover what they like.