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Izuku has lost count of how many times he has rewatched the five seconds of footage capturing Pro Hero Carbon’s use of his Quirk, Replicate, scouring the images for as much information about its functionality as possible, but it must be pushing forty at this point.
Between that and the freshly filled page of notes on the desk before him, he wouldn’t be surprised if he’s been dead to the world for at least twenty minutes. Thankfully, the only other student in his room - Todoroki Shouto, second place in their third and most recent Sports Festival, son of the Number One Hero, and Izuku’s boyfriend of almost a year - seems happy to sit in silence for hours on end, doing homework or reading a book, cross-legged on the floor beside Izuku’s bed.
Silence, that is, aside from Izuku’s muttering, a habit that it seems he’ll never be able to break, and one that he fails to notice himself currently engaged in.
“Five fingers… like Uraraka-san’s Anti-Gravity, or- that villain, it doesn’t seem to activate until all five fingers connect with the source material… but if that’s how it activates, how does it deactivate? How does Carbon return to his normal form? A time limit, maybe… or some kind of voluntary release… it’s not like there’s a material he can replicate to return to normal, unless…”
He’s so absorbed in his thoughts that he does not realize Shouto has moved until arms wind around his waist, soft lips brush against his neck, silky hair tickles his ear.
Izuku almost jumps. “Sorry!” he exclaims automatically. “Sorry, I distracted you, didn’t I…? I’ll be quiet,” he adds, embarrassed, but the words are barely out of his mouth before his boyfriend’s hands slip under his t-shirt, exploring the bare skin beneath as his lips continue to press gentle kisses against Izuku’s neck.
Heat rises in his cheeks. Oh. Oh. Okay. This is fine - his notes can wait–
“Keep talking,” Shouto says, low and steady and centimeters from his ear, and Izuku freezes, blinking with confusion. Keep... talking? About… that Quirk?
He... supposes he can do that.
Izuku forces his gaze back down to his notes, swallowing. “U-um– okay… where was I?”
“Deactivation,” Shouto answers.
“Right! D-deactivation… I-I guess it could be a case of using the Quirk on another human, but… there’s no evidence it can even be used with anything biological - steel, concrete, water, everything we've seen him replicate is inorganic, so–”
Shouto resumes his ministrations, hot breath against his earlobe, fingers mapping the contours of his torso with the same attention to detail that Izuku gives his analysis, and Izuku finds himself shivering, his skin tingling in the wake of his partner’s touch.
“A-and, if- if it could be used with organic matter, that would raise so many questions - it seems like it would only mimic the surface material, like -” he swallows, chest rising and falling under Shouto’s palms “- s-skin... but then... i-it must be copying on a molecular level, altering the cells in his b-body to- to–”
Izuku’s voice gradually rises in pitch until Shouto’s fingers brush over his nipples like feathers, and he gasps, Carbon’s Quirk instantly forgotten. He turns, breathless, sending Shouto to his knees as he almost stumbles from his chair to wrap his arms around his companion's neck, bringing their lips within inches.
“Shouto–”
“Izuku,” Shouto responds, so quiet and breathy it’s almost a whisper, holding Izuku’s waist as he all but climbs on top of him. “Keep talking...”
Izuku stops, and stares. What...? He can’t be… is he seriously…?
Shouto holds his gaze, a noticeable pink flush comfortably settled in his cheeks.
He is - he likes - oh - oh.
Izuku feels the temperature in his face hike up a few notches. Most people find his monologues annoying at best, or downright creepy at worst… the thought of Shouto not only tolerating it, but enjoying it - the thought makes his heart swell inside his chest, makes him want to trip over himself ten times over to give Shouto whatever he wants. How could he possibly refuse?
“O-okay, um,” he begins, trying to both remember what he was talking about and keep his voice steady. “R-right, organic matter versus inorganic… so… s-so far it doesn’t seem like… like organic matter is a viable source material, a-at least, from the information available to the public, s-so… so it’s probably safe to assume that… that…”
Shouto’s lips are back at his jaw, gently lowering his body to the floor, and Izuku’s heart threatens to burst through his ribs with the force of its palpitations. Keep talking.
“T-that it can’t be used as a source… but that… that’s not even– I- I mean, if it’s molecular replication, then how– how can he even move? The number of different kinds of cell required to m-make a functioning body, how is that - h-how can concrete or steel have the elasticity required for normal motion? A-and that’s not even mentioning– w-water-!” he says, a little too loud as Shouto shifts lower to drag his tongue across a nipple after lifting Izuku’s shirt. It takes everything he has to not simply devolve into gasping Shouto’s name.
“H-how– d-does the physical state- i-if it’s not solid, then– h-ahh–!”
Izuku throws an arm across his face, as if hiding as much of it as possible will quiet his cries by extension, his back arching away from the floor with the new stimulation of what he can only assume is Shouto’s free hand pressing, rubbing, delicately and torturously squeezing his rapidly stiffening cock through his shorts.
“Hnn- S-Shouto- Shouto, oh my god-”
“Keep talking,” Shouto encourages, soothing, gentle.
Izuku scrunches his eyes shut in an attempt to focus - focus -
“Ahh- i-i-if water is- v-v-iable, then h-how- how does it keep- p-physi-cal... aah! F-form, how does it-”
He manages - for the thirty seconds between Shouto’s request and the moment firm fingers slip under the waistband of his shorts to slowly, methodically tug them down.
Keep talking, keep talking-
“C-control– how- c-can- w-without a- a Quirk that controls w-water, how-”
He can’t help peeking through the arms that somehow grant him at least partial relief from the waves of self-consciousness that never fail to envelop his being in these moments, and his face burns at the sight of Shouto, on his knees between Izuku’s legs, hands coming to rest on his hips, face flushed, mouth open to drag his tongue up–
“Ohgod- S-Shou–”
It feels like every nerve ending in his body is suddenly, inexplicably concentrated within the few square inches of skin currently in contact with Shouto’s tongue, pleasure driving the mere concept of coherent thought from his mind like a tsunami.
Keep talking–
What was he even thinking about?
“C-can’t- be- c-control–”
His attempt at speech dissolves into gasps and aborted moans as Shouto takes him into his mouth, hips twitching under his hands.
“Shouto- S-shou- I c-can’t-”
“Try,” Shouto whispers, breath chilling the saliva now coating Izuku’s glistening tip- water-
“W-water- water can’t- i-it’s not solid, it- s-so how- how c-can- Quirk-”
Izuku watches him, trying to focus on something that isn’t the overwhelming sensation rolling through his body with every stroke of Shouto’s tongue, hot and soft but with enough texture to send his mind into another dimension. It doesn’t help, the image of Shouto’s lips on his darkened skin, fingers firm yet gentle against his base, eyes closed as he hums with satisfaction only ensuring the total, complete cessation of intelligent thought keeptalking–
“W-water- water’s- haahh-”
The back of Izuku’s head hits the floor, and he attempts to grip the surface with his fingers, instead only scraping it with his nails.
“S-Shouto- Q-Quirk- c-can’t– Shouto, I’m- I c-can’t! I’m gonna-”
It’s barely two seconds before the pool of ecstasy building in his stomach overflows, spilling white-hot excess into his muscles, his skin, his tendons and nerves, and he’s choking back a cry, fingernails making unintentional indents in the floor of his dorm room as his hips roll into Shouto’s palms erratically.
When he finally comes back to his senses, he’s vaguely aware that he’s trembling, eyes opening blearily to find Shouto’s eyes locked onto his own, cheeks colored a deep pink, lips slightly parted, staring at him with… surprise? Astonishment? He almost looks… amazed, a drop of pale, translucent liquid trickling down his left cheek–
Izuku makes a high-pitched, panicked noise, sitting up like the floor shoved him. “Oh- oh, god, I’m sorry! I s-should have–”
Shouto blinks, following the line of Izuku’s gaze, and simply lifts a hand to wipe himself clean. “No… it... it was good,” he says, averting his gaze, his cheeks no less flushed.
Izuku doesn’t miss Shouto’s left hand shifting between his legs to adjust the fabric and, presumably, its contents. He swallows.
“Do… do you want me to keep talking?”
Shouto finally meets his eyes again, staring in stunned silence.
And nods.