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Heavy breathing fills the otherwise silent air. Now and then, the bed frame creaks. Sukuna’s movements slow inside of him and Yuuji bites his tongue, suppresses a whimper. His hands slide over his brother’s back, slick with sweat, tracing the vast expanse of skin, feeling goosebumps rise beneath his fingertips. Sukuna rocks forward again and Yuuji lets out a low hiss, nails digging into his brother’s skin, no doubt leaving marks behind.
“Fuck,” Yuuji groans, tilts his head to the side to place a kiss against Sukuna’s temple. He can taste his salty sweat on his tongue. “Move, fucking—come on, move,” he adds, digs his nails further into his twin’s back until he can feel the skin give and break.
Sukuna whines, high in his throat and it’s so fucking hot, Yuuji thinks he’s going to come right then and there just from this sound alone. Sukuna always gets so needy and it’s a rush of adrenaline shot straight into his veins, knowing that he’s the reason his brother is falling apart like that, knowing that he desires Yuuji so much it drives him insane. It’s a far cry from the Sukuna that everyone else knows. Here, when it’s just the two of them, sharing every breath like they used to share clothes and toys, Sukuna lets go of every pretence.
He buries his face further in Yuuji’s neck, teeth grazing over the sensitive skin there, not daring to go any further without his brother’s permission. “Please,” he mutters, voice muffled but Yuuji can hear the neediness all the same. “Please, Yuuji, please let me,” he begs and, fuck, how could Yuuji ever say no to him when he knows how to beg so sweetly?
His hand slides up his brother’s back, fingers resting on the back of his head and threading through the short hair there. He inhales, nods his head. “Okay, go ahead,” he whispers quietly and under normal circumstances he’d fear maybe Sukuna hasn’t heard him but he knows his baby brother is listening intently, waiting for Yuuji to tell him to continue.
Sukuna sobs with relief, hips rocking forward in a harsh thrust and Yuuji’s vision whitens out the moment his teeth bite down into his neck, sharp canines puncturing his skin immediately. His eyes close on instinct, a stuttered out ‘God, fuck’ the only incentive Sukuna needs to keep going, to keep driving his cock into his brother while he bites down more harshly, tearing through skin and muscles.
Yuuji feels lightheaded, his blood rushing from his head down towards his own weeping cock. The sheets below him are soaked red as Sukuna feasts on the meat of his neck. He chews obnoxiously loud, slurps up Yuuji’s blood and if Yuuji wasn’t so out of it, he’d scold him for being so messy. Still, he doesn’t slow down, continues to fuck into Yuuji until he comes to a stuttering halt just as he’s swallowing down the last of his brother’s neck.
Yuuji’s grip tightens on Sukuna’s hair and he pulls his head back and away from his shoulder, taking in the sight before him. Sukuna looks fucked out, eyes red rimmed with tears, pupils blown wide, Yuuji’s blood dripping out from the corner of his lips and smeared all over his chin. His brother looks like the animal everyone believes him to be. Something hot coils in Yuuji’s stomach.
His hands come up to cradle his face, thumbs tracing over the identical twin marks under Sukuna’s eyes, two crescent moons, just like Yuuji has them. Without thinking, he pulls his head down, crashes their lips together and licks into his brother’s mouth with a desperate whine lodged in the back of his throat. Sukuna doesn’t resist, lets Yuuji claim his mouth like he’s claimed every other inch of his body, too. Yuuji chases the taste of himself, licks up every trace of blood he can find, consumes the leftover bits of his neck that his brother hasn’t swallowed down yet. He comes, then, with a cry against his brother’s lips, cock twitching between their bodies, soiling both of their stomachs.
Yuuji pulls back to take a much-needed breath and Sukuna immediately crashes down against him, collapsing like a wet sack of potatoes on top of him. It’s not comfortable, his chin digs into the still open wound that used to be Yuuji’s shoulder.
“’Kuna,” he gasps wetly, patting the other’s cheek a few times. His brother groans, shifts a little and places a hand on his upper arm.
“I got you,” Sukuna says, voice raspy and low and out of the corner of his eyes, Yuuji can see the black lines on his face appearing as warmth floods his body, the flesh between his neck and shoulder slowly knitting itself back together as Sukuna’s Reverse Cursed Technique stitches him back up. Yuuji relaxes, then, too and his hand finds it’s way to the back of Sukuna’s head again, fingers carding through the strands of hair.
“Hey, ‘Kuna?” He mumbles, stifling a yawn. Sukuna grumbles in acknowledgement, though Yuuji can hear that he’s drifting off already. “Can you leave the bite mark?” The grip Sukuna has on his arm tightens for just a moment and if he were to guess, Yuuji is sure a spike of arousal just shot through his brother’s body. He suppresses a satisfied smirk when he detects Sukuna’s face reddening. The blush even reaches his ears.
Sukuna may be the perceived animal between the two but the truth is, that Yuuji isn’t quite innocent, either. He wants people to see and wonder. He wants them to know what they’re doing and most of all, he wants to show it off. He wants people to take one good look at him and see the marks his twin has left behind.
“Yeah. Okay,” Sukuna replies and his voice sounds hoarse but for different reasons now.
“Good. You’ve done well.” His twin shifts at those words, buries his face deeper in the crook of his own arm. Yuuji watches him fondly, gives his hair one last tug of acknowledgement before closing his eyes. He is bone-tired, a pleasant soreness all throughout his body. Within minutes, sleep has finally claimed him, not before registering a feather-light kiss to his cheek, though.