Dean doesn't eat, just drinks whiskey like clear cold water. He orders Sam peach pie and licks the taste of it off Sam's lips, and Sam begins to crave sweetness for the first time since he was a child enamored of marshmallow fluff.
Dean doesn't sleep, either. He sits by the window, curtains drawn a little, watching the headlights of the cars going by, and Sam gets used to the streaks of brightness across his eyelids, learns to fall asleep to the sound of Dean sharpening knives or disassembling and reassembling the same guns over and over. Sometimes he wakes in the middle of the night, sleep-fogged and still drifting, and in the morning he can't tell whether he remembered or dreamed the press of Dean's hand against his heart or the base of his spine.
Dean still drives, though: dark glasses on and windows down, singing along like a rockstar to his favorite albums and elbowing Sam until he joins in on the choruses. For the first time in years Sam begins to remember the carefree moments they'd had as boys, the heady days when Dad had finally given Dean permission to use the car and the Impala had become Dean's baby. The distances between hunts become elastic, like the warm expansive summer nights they'd reveled in the year before Sam left, only this time the endless road is all theirs.
It's too good to be true, Sam knows, back in his hindbrain where John had drilled certain reflexes deep. There's a catch somewhere--there always is. But it doesn't come and it doesn't come, and Sam gets into the habit of eating burgers on Dean's behalf, just to see the way Dean watches with eyes both pleased and longing. Dean's jokes are still dumb, and his hands still steady when he aims a shotgun, and the only thing that makes him flinch when they go hunting demons is a knife held too close to Sam's eye.
Each night Sam falls asleep sated to his bones and every morning he wakes hungry for more of the same, and day by day Dean feeds him all the things he didn't know he'd spent a nearly lifetime starving for.
It's platonic licking, I swear. Please don't revoke my gen writer's card.