Sam's no match for him, and while that would've bothered Dean in the past, he doesn't give a shit, not now that all the weight has been lifted from his shoulders, all that responsibility that never amounted to anything anyway.
Dean walks into Sam's bedroom, not knocking, not hesitating, and it's so fucking fun to watch the way Sam's eyes widen, the way his lips open slightly, the way he sits up straighter on the bed, suddenly conscious of his lack of shirt and jeans in a way he never was before around Dean.
"Uhm, hey," Sam says nervously, setting his book on the bed next to him and glancing at the spot on Dean's arm, where he knows the Mark of Cain is. "What's going on?"
"Well, see, here's the thing," Dean says, holding his arms out before resting them on his hips. "I've come to realize that all the hangups I've had all my life just don't really matter."
"Okay," Sam says, nodding.
"In the grand scheme of things, who really gives a shit if my brother checks out my ass whenever I wear tight-fitting jeans?" Dean asks, grinning.
Sam's cheeks turn pink. "Dean, I didn't mean to-"
"No, Sammy, it's okay," Dean says, shaking his head. "That's exactly what I'm talking about. I've wanted to fuck your tight ass for years now, but because I always have to be responsible and you're my baby brother and all that other bullshit, I've held back."
Sam opens his mouth, but nothing comes out. He glances around the room, as if some answer will pop out at him, but then he looks back to Dean, and Dean's pleased to see there's some interest in his eyes along with the fear.
Because this new Dean isn't just devoid of morals. He's not some monster. He's just free of anything that held him back before. The shoulds and shouldn'ts just don't matter. Dean still has no desire to randomly mow people down with his car, but he doesn't have that little voice in the back of his head saying he needs to be good.
"Dean, maybe you don't want to-"
"Oh, but I do," Dean says as he pulls his shirts off over his head and drops them on the floor. "You've been mine since the day they let me hold you. You're still mine. And now I'm gonna claim what's mine."
Sam gasps, scooting back on the bed even though he's already sitting against the wall. Dean pounces, yanking Sam down the bed by his knees and getting between his legs, grinning down at Sam.
"You look adorable when you're trying to be a good boy," Dean teases, poking at Sam's belly.
"Dean, c'mon," Sam says, trying to sit up, putting a hand on Dean's chest, but not pushing. "You don't wanna do this."
"No, I really do," Dean says, fingers grazing the slit of Sam's boxers.
"Dude, stop!" Sam says, squirming and pushing at his hands.
"You were so much more open to new things when you didn't have that pesky soul," Dean says, chuckling. "At least when you were soulless, you didn't make any excuses for doing shitty things like leaving your brother in purgatory."
Sam freezes, his eyes going impossibly wide. "I-I thought you were okay with that. I moved on. Like you told me to do!"
"I only said I was okay with it because you would've been all pouty about it otherwise," Dean says, reaching into the slit of Sam's boxers and wrapping his fingers around Sam's cock.
Sam whimpers, closing his eyes, and very obviously not that upset with the stimulation his cock is getting. It's been too long since anybody touched it, and Dean finds it amusing that Sam is so easy.
"Stop!" Sam says, eyes opening and his hands more forceful as he pushes at Dean's shoulders.
"Oh, I don't think so," Dean says. "I'm already hard, and I wanna see just how tight your hole is."
Sam's had enough, and Dean can see when his little brother finally realizes this isn't funny anymore.
"Dean, stop!" Sam says, the fingers of his right hand jabbing out to catch Dean in the throat.
Dean easily stops him by grabbing his wrist and twisting. Sam yelps, and Dean lets go, chuckling at the wounded expression on Sam's face.
"Don't fight me and you won't get hurt," Dean says flippantly.
Sam flails, trying to get a punch in while simultaneously trying to roll them, to get Dean off. Dean moves with it, lets Sam get a punch in so he can start yanking at Sam's boxers. The sound of material shredding is loud in the room, as is Sam's yelp of pain, most likely from the material catching his balls, and Dean pulls until the boxers give and come off, the shreds lost in the folds of the blanket beneath them.
"Wait!" Sam says, squirming and panting. "Stop! Dean, you don't wanna do this! Stop!"
"Come up with a better line, baby brother," Dean says as he reaches under the pillow, where he knows Sam's bottle of lube is. They grew up in close quarters, know way too much about each other, and soon enough Dean's flicking the top open.
"Dean, please stop!" Sam yells as Dean braces his right forearm over Sam's chest and shoves his hand between them to squirt lube directly on Sam's hole.
Dean tosses the lube, then shoves three fingers into Sam's hole. "You're not as tight as I thought you'd be," Dean says, then chuckles in Sam's face.
"You know I fuck guys," Sam hisses, reaching up to choke Dean.
Dean grabs his balls and squeezes, Sam's hands loosening immediately. "I wouldn't suggest trying to knock me out. You might kill me, and this right here will look like nothin' once I come back."
Sam lets out a noise of distress as Dean shifts. He tries to hit Dean's shoulders, his chest, even his face, but Dean just chuckles and shoves his cock in Sam's hole.
"No!" Sam yells, his entire body tensing as Dean bottoms out.
"You know you wanted it, Sammy," Dean says as he starts thrusting in and out of Sam. "Think of this as a free pass. You get laid, you get to see what I'm like in bed, and when it's all over, if you wanna go again, you just ask. I'm not hard to get along with."
Sam squeezes his eyes shut and grits his teeth, his fingers digging into Dean's forearms. Dean can feel something inside him shift, something that feels very right, because as soon as he was inside Sam, as soon as his baby brother was truly his, Dean felt complete. The truth was that Sam never needed Dean, but Dean needed Sam, and now he had him.
"You wanna come too?" Dean asks, then bites down on Sam's left shoulder.
"Fuck!" Sam yelps, twisting away from the pain.
"Aww, but I thought you liked biting," Dean sing-songs.
"Get off of me," Sam says, voice low. "You got your way, now get off."
"I'm almost there," Dean says, grinning down at Sam when Sam opens his eyes to glare at Dean. "You sure you don't wanna come too? I don't mind giving you a little hand action."
"No," Sam says, voice tightly controlled.
"Your loss," Dean says, then starts fucking into Sam so hard the bed squeaks and Sam's body tenses up. "But I think you're missing out on an awesome opportunity. I know you've had a thing for me ever since you were a teenager, and before I had this sense of freedom, I bet you never even noticed. So take advantage of it now, Sammy."
Dean can see the realization in Sam's eyes, and he feels a sense of victory, because Sam never knew that Dean knew, and Sam never knew Dean felt the same way. But it didn't matter, because now Dean was taking something that wasn't offered, and any fun in the future would have to be taken instead of given. That was okay with Dean. The loss of all those hang-ups was the best thing that ever happened to him.
"I'm gonna come inside you, little brother," Dean says, looking Sam in the eye, watching as that last bit of hope dies. "Oh, fuck, yeah," he groans, writhing all over Sam instead of pounding into him as he fills Sam with his release. "You feel that? It means you're mine. Every part of you is mine."
Sam stares off over Dean's right shoulder, lips thinned out in an almost-pout, brow furrowed with anger and pain. Dean pulls out and sits back on his heels.
"You really should've let me at least give you a hand job," Dean says, as if he's disappointed. "You would've had much more fun," he says as he pats Sam's left inner thigh.
Sam doesn't move or acknowledge him, doesn't move, and his breathing remains shallow, controlled.
Dean shrugs as he gets off the bed. "You hungry? I'm hungry. Stay here and I'll go get us something to eat. I'll make your sandwich just the way you like it."
He walks out of Sam's bedroom, his jeans still open, cock still hanging out. He feels good, right, complete in a way he hasn't for decades. But he's also hungry, so he heads for the kitchen.