He knows what to say, where to aim, to cut the deepest. Dean knows how to knock his brother down, how to hurt him the most, and how to do it the quickest with the most amount of damage. Dean could use his words alone to kill his brother. He knows Sam could do the same. So he doesn't. Doesn't go there, doesn't want to, doesn't bleed them both dry over something neither of them can control. The rest of the world does enough of that for them.
He's got his hands on his brother and it's as natural as breathing and just as comforting except he is hurting his brother and that's...that's just as natural but not nearly as comforting. He's got his hands on his brother and it hurts. He isn't sure how they got to this point but they are here and right now, he really wants to just punch his baby brother in the face until he isn't moving anymore.
Sam is hitting him. Hard. He's hitting him but not like he hits monsters because that kind of graceful violence is reserved for the cover of dark. When no one can see how much pleasure comes of it. So he holds back when he swings at flashing green eyes. Only hits hard enough to bruise. Maybe hard enough to crack a rib here or there. There's some blood, but when isn't there?
It's hard. Holding back is hard when all he really wants to do is hurt Sam until his stubborn little brother realizes he is being stupid. It's hard because he likes the feel of flesh giving away beneath his knuckles. It's hard because it's his brother and his family and neither of them should enjoy hurting each other as much as they are. They both know it and both hate it, yet neither can stop and besides, if no one tells, it's like nothing is wrong with them.
Punching, kicking, quick maneuvers and jerks back to avoid pain. It's all too familiar. Something they've been doing since they were kids getting into an argument on a dirty, filthy motel room floor. It's the exact same. Except Sam's bigger now, and a little too jaded. A little too insane. It's exactly the same. Except Dean's colder now, and a little too jagged. A little too dead inside.
Dean's got Sam on the floor and he's got his hands on his brother. He's got his hands on his brother's throat, and it's so damn familiar, just another motion to go through, that he doesn't think anything of it as Sam's breathing falters and stutters and becomes a little too rapid, a little too labored. He doesn't think anything of it, his hands wrapped around Sam's throat, until that familiar, determined, stubborn pulse flickers. Until it flickers, nearly fucking goes out, and Sam's huge, scarred hands aren't grasping at his equally scarred wrists, aren't trying to claw his skin off because his brother can't breathe.
Dean's off Sam and halfway across the room, the state, the damn world, before he can process past 'ohshitohshitSamshitSammy'.
And Sam.
Sam isn't moving, still isn't breathing, so he probably isn't alive, and of course it would be Dean to be the one to finally kill Sam. Stubborn, invincible, strong Sam. So Sam is dead because he isn't breathing, and Dean doesn't-can't-he can't-why didn't-he doesn't know what to do because Sam isn't breathing.
Dean's pretty sure he makes a noise, a whimper or a scream or maybe a name, but he can't hear past the litany of 'SamSamSammywakeupShitSamI'msorry' and his own traitorously strong heartbeat. Traitorous because Sam isn't breathing so his heart isn't beating which means Dean's shouldn't be either. But it is. And he can't hear past it and the sound of panic. Until a quiet, painful, desperate gasp echos too loudly in the deafening silence of the random, trashed motel room they are staying in.
Relief, plain and simple and beautiful, makes Dean's legs shake, and he blames it on exhaustion for the way he damn near crashes back against the wall and slides down it because his body is checking out on him. Bodily function is leaving the building, leaving him helpless and weak and so damn relieved.
But then hazel eyes blink open and stare at him. Sam knows, knows the sick pleasure Dean felt and how he didn't want to stop, and understands. He isn't angry or shocked or disgusted or afraid. He's so damn sympathetic and understanding, 'Sammy has always been too understanding for his own good', that Dean makes another noise, this one higher and more strangled than the last, and runs. He's out the door and flying out of the parking lot, leaving the smell of burnt rubber and the echo of squealing tires, before Sam can draw in a third breath.
When he comes back hours, maybe days, later, he finds Sam sitting calmly on his bed with their weapons bag open. The knives and guns and bullets and salt are all spread around him, like a kid with their toys, and he's busy cleaning Dean's gun. Tired, calm eyes flick up to meet his before green eyes dance away and then Sam's gaze is back on the gun, hands moving confidently, mechanically. Dean glances at his little brother, who looks too young sitting there hunched over on the bed and too old with that gun in his hands. There's a hand shaped bruise imprinted on his skin, and Dean knows his throat has swelled because there's this high, thin whistling noise everything Sam breathes, 'at least he is breathing', like he is congested.
Dean scratches at the dried blood above his right eye and sits on his bed, slides underneath the blankets like the room isn't in shambles or there isn't a hand shaped bruise that fits his hand imprinted on his brother's skin, wrapped around his pulse point, or there isn't a stinging persistent pain in Dean's left side, or blood crusted over both of their table is broke and so is the tv. Their neighbors left during the peak of their violence, and the office clerk isn't coming around.
Sam switches off the light and lays down surrounded by weapons, and Dean falls asleep to whistling and burning in his chest.
It's all too familiar except it isn't.