When Sam first comes back from Hell, it's all about touching.

Dean doesn't notice it at first, not really. He's just too busy being happy that his brother's home, and it starts off so small anyway that it's easy to overlook. But as the weeks go on Dean starts to notice those little things. Like the way that Sam will lie on the bed and have one foot on his duffle bag, fist thumping regularly on the bedside table, one arm curled around a pillow, and his other leg hanging off the bed to touch Dean's bag, which usually somehow finds its way propped up on the bed right within his reach.

The fifth time this happens, Dean starts to realize it's not coincidence. And that's when he notices the other things: the way Sam will run his hands over the Impala's hood in smooth sweeping circles like he's not sure she's solid. Or how he spreads out all of his belongings on his bed before he goes to sleep—and even then, doesn't sleep well. He keeps one hand out all the time when they're walking, running the flat of his palm over whatever building is beside him, thumping his fingers across light posts and stop signs.

And when they're working a case, if Dean asks Sam to come over and look at something, his brother will stand so close it's almost like Sam is crowding him, his elbow always brushing Dean's. When they're in the car, Sam will drape his arm across the back of the seat, hand hanging against the side of Dean's neck with a spider touch that raises the hair on Dean's arms.

Dean doesn't say anything, until the day he's sitting on his own motel bed, cleaning his gun. And Sam walks in, looking sunken-eyed and sleepless. He sheds his jacket, walks over to the bed, and drops down so close to Dean that their knees are almost in contact. And then, carefully, Sam leans his shoulder up against Dean's.

"Dude, what gives?" Dean snaps.

Sam looks at him, all innocent surprise. "What?"

"What's with this whole cuddly deal? You're like a psychotic cat."

Sam's face falls. "Dean…"

"And you think I haven't heard you tossing and turning all night? You gotta get a grip, man, seriously."

"Don't do this to me." Sam says, and the plea is so heartfelt and so quiet that it stops Dean cold in his questions, not even knowing what it is he'd doing wrong.

Sam sits there with his eyes closed, then scoots away. And somehow the space that's between them now feels deeper and wider and emptier than anything Dean has ever known, so full of pain he doesn't understand, and he wants to drown in it.

"I'm just making sure." Sam finally says.

Dean sets his gun aside. "Making sure. Making sure of what?"

"That it's all real, Dean." Sam says. "In the cage, things that Lucifer made—they were always cold. Like touching dry-ice."

Dean remembers standing with Sam beside the Impala a few days before, watching his brother hold one hand over a patch of black hardtop that had to be hot enough to burn. But Sam hadn't moved, and Dean had just labeled it as one of those strange things Sam sometimes did, ever since he'd gotten his soul back, and he never thought about it again.

Maybe the burn was the whole point.

"It's like I need something," Sam goes on, softly. "Something to anchor me to the world. Because, this? All of this? I saw it in the cage, Dean. I watched all of it burn to the ground." Sam peers at him sideways through a scruff of dark hair. "Even you."

Anchors, Dean thinks bleakly. All of those things that Sam touches—the weapons, a motel bed, the car, the bag where Dean keeps his things—these are the real world to Sam. They're all he's ever had. And when he watches them, he's afraid they'll be stripped away. The only thing that tells the truth against the deception, against the pain he lived in for years in the cage, is his own touch. The only thing that won't lie to him.

Whether it's hands-in-his pockets Sam, or sprawled-on-a-hotel-bed Sam, or fighting Sam, or any other kind of Sam, it's always the Sam that's afraid he's going to wake up back in Hell. And the things he holds on to, the things he's always touching, are the things he's terrified to lose.

The thing he's he touches the most, though, Dean realizes, it's him. It's Dean, Dean is his anchor, the one thing that's always around to prove to him that he's not about to step over the edge and back into the cage. Back into countless more years of suffering.

"This isn't Hell, Sammy." Dean says. "It's not gonna burn."

Sam looks at him, helpless. "You can't know that for sure."

And after all this time he's been back, it's like Sam isn't really all here. He thinks he's still in a dream and he'll wake up to a nightmare.

"Actually, I do know that." Dean says, bracing his hands on the mattress. "Because I'm not gonna let anything happen to you." He shifts a little bit. "Sam? I want you to look at me and tell me that you know this is real."

Sam looks at him, with eyes that are so full of trust but still cautious, still wary. As if saying those words will somehow make them less true. "This is real."

He doesn't say that he knows it. And Dean can see that it will still take time for Sam to realize this the world isn't an illusion. That everything about it and in it is painfully, terrifyingly, purely real. And that it's where he belongs.

"I'm right here and I'm real." Dean says.

Sam bows his head with a nod. "I'm trying, Dean."

But he still looks so lost.

"Hey. We've got time to figure this out. I'm not going anywhere, Sammy."

And just to prove it, Dean slides over and leans his weight against Sam's shoulder.