There's something special, something remarkable, something hidden about Dean. The life he's had, outwardly he should be marked up and scarred, but at a glance there's only fresh, freckled skin, youth and beauty. Up close, there's far more to see.
Sam's the only one who sees it, most of the time. Other people get close, but they're colored by first impressions. Some girl Dean picks up in a bar, smoky and bad lit, she'll only ever see the perfect, the pretty. She'll see the smile and the smooth skin and the white teeth and the sparkling eyes. She'll never see him in daylight, and if she does, it'll be through the bleary eyes of the morning after and then he'll be gone.
Dean never walks with shame. Sam picks him up outside, a motel, a suburban house, an apartment building, and sometimes it's in the bright, bright sun of morning, or it's the weird glow of pre-dawn, and he never drags his feet and he never drops his head except for maybe a little of that bashfulness when Sam looks at him. And how does that even exist, in him, in Dean, when he's seen the things he's seen and he's done the things he's done.
Dean should be hardened, the life he's led. Been killing things since puberty, Dean has, he's known about the monsters and the demons far longer. At twenty-seven years old, Dean should be older.
He is, on the inside, but he's got a way of hiding it. Sam sees through, the carefree grin, the light step, he sees through the fun Dean has when he's separating a head from a neck or driving silver deep into a heart.
And he sees it when the door is closed and the bare, cold motel bulb picks out every scar and fading bruise. When he unwraps Dean like a gift and counts every nick and cut and line of puckered skin dotted with years-old stitch marks.
Sam wonders if the girls even see them, if they bother to let their fingers linger like Sam's do, if they touch every one and wonder how it got there.
There's more than a few Sam still wonders about, but they don't talk a lot about when he was away. The hunts he wasn't there for, the cuts, the bruises,the bullet wounds. He knows his father's stitches, no where near as fine as Sam's own, and he can pick those ones out. But there's others, finer, almost invisible, and Sam wonders if Dean went to hospitals when he hunted alone.
There's a fine, white line behind Dean's left ear, never stitched, healed nice but not perfect. Sam wonders if anyone else has even noticed it, if Dean even knows it's there. Injuries pile up, hunts fade into one another, and maybe he doesn't remember.
Sam kisses it, sometimes, drags his tongue along the line, just to see if he can feel it. He can't, not with his tongue. Too many scalding coffees drunk too fast, endless nights of study and too many hasty morning bugouts to count. Dean shivers when he does it, though, shakes and pants for breath, so Sam does it again.
There's something of Dean, the stuff buried deep down, that comes out in his eyes, in his moans and whimpers when it's dark and there's neon flickering outside the window and they're pressed together, skin to skin, in a too-small bed. Sam'll bet everything he has that Dean's girls never see it, never hear the soft pleas, never feel Dean's hands, soft and smooth on the backs, rough, callused palms, clinging to them like Dean clings to Sam in the night.
They never feel Dean soft and twitching, clenching around them, never inspire the trust he puts in Sam when he surrenders.
They can't. Emotionally, physically, they're not capable. They haven't been there, haven't fought, side by side and sometimes head to head. They've never been knocked back when Dean's fist hits their jaw, never been shoved up against a wall, and they've never pushed him down, held him until he stops struggling.
They've never felt Dean surrender, like he only ever surrenders to Sam, never felt him push back, asking without words, because Dean never uses words for what they do together and Sam gave up trying years ago.
The hardest thing Sam ever did was leave, and not because of duty and not because of family, but because he wouldn't wake up every morning and see what no one else could.