The room is always dark.
Izuku likes it better this way and he thinks maybe Kirishima does, too. In the dark, Izuku’s freckles disappear and his scars can belong to anyone. In the dark, only the red of Kirishima’s eyes catch the moonlight, made cold by the silver-white glow and in those moments they can almost belong to…
Izuku doesn’t like gentle. He wants to hurt and to bleed, he wants marks that he can prod with blunt fingers in the light of the day or in the solitude of his own room, hand wrapped around himself as he fantasizes about burnt-sugar sweat and broken glass words. He comes, every time, with the wrong name on his lips.
Tonight is no different. The lights are off, the sound of heavy breathing fills the room, and Izuku drowns in the sensation of large hands pinning him to the wall, of sharp teeth dragging along his neck hard enough to break skin. His cock aches where it’s bare and pinned between them, chafing against the rough material of Kirishima’s pants. He’ll have bruises on his wrists in the morning, but that’s perfect, that’s what he needs.
Kirishima spins him around, shoves him up against the wall hard enough that Izuku’s forehead knocks against the surface before he can catch his balance. A buckle rattles and cloth hisses as pants slide down tone legs and hit the floor with a dull thud. Izuku groans and struggles to keep himself upright, fingers digging into the cheap walling until it peels beneath his dull nails.
Izuku shivers and in his head he paints smoke over the syllables until they resemble a growl and they curl within his chest with enough menace to choke him. He revels in the sensation, lives on the inability to breath as he slips further and further within the confines of his own imaginings. The hands digging into his side are hard and they’ll leave bruises that in the light of day will excite Izuku but riddle Kirishima with guilt. Izuku should care about that more than he does, but he can’t. He wants this, needs this, and he’s too selfish to give it up. He squirms directly against orders, seeking retribution. “Make me.”
Izuku’s pulled back by the hips and forced forward at the waist with enough force that he almost knocks his head against the wall a second time. His hands shoot up and his fingers find the grooves he’s just carved into the surface. He legs are kicked open wide and his asscheeks pried apart to allow space for the wet cock rubbing between them. Izuku has no other warning before the head breaches him and the base splits him open, punching his breath and a moan out of him in one, violent push. Fuck, it hurts, but Izuku struggles back, wanting more, needing more, just more, more, more .
Kirishima gives it to him, keeps him at a painful arch with one large hand in the middle of his back and holds him in place with the other on Izuku’s hip as he drives into Izuku hard and fast enough that Izuku can’t catch his breath; each inhale stops halfway and expels past spit-soaked lips as breathy, messy moans and half-strangled screams. His insides burn, molten hot with desire and a building orgasm that threatens to tear him apart at his very seams. He forgets for a moment where he is, who he’s with. When a hand wraps around him and the pressure overwhelms his bones and pops his every stitch, scouring his insides of everything but bright, sharp pleasure, he loses all control of his tongue.
“Ka—Kacchan," he groans and it’s quiet in comparison to his breathing. His cum spills over the hand wrapped tightly around him and paints the wall in thick splashes. The strength drains from his limbs as if someone has slashed through every bit of tendon and sinew holding him together. Kirishima doesn’t last much longer, his last few thrusts disjointed and harsh before he suddenly stills and warmth floods Izuku’s insides.
Coming down, he thinks he should feel guilty, gasping the name of someone who isn’t his boyfriend, but he swears in between their humid panting, he hears—just as desperate, just as reverent—a whispered Katsuki breathed into the skin of his neck. So the guilt doesn’t come.
Afterall, Kirishima's the only one who understands what it's like to love the sun and never have it love them back.