It's at times like these that Dean misses sleeping in the Impala, stretched out on the bench seat, Sam snoring in the back. Well, he's always missing the Impala, and Sam, but especially at times like these.
There's no fire to keep Dean warm, no sheltering cave walls, just the boughs of a freakishly hand-like tree, covered in dripping wards painted in Castiel's blood. Dean is half-afraid that the branches are going to clamp shut at any moment and squeeze the life out of him. He thinks that there's no way he'll be able to sleep like this, but he's so exhausted that he passes out as soon as he closes his eyes.
Dean opens his eyes, and yelps in surprise. He's half-hanging off the branch, and his brain is telling him that he should be hurtling to the ground, but he's not. He scrambles into a more secure position, and sees Cas, leaning against a neighbouring branch, staring at him, heavy-lidded and unfocused.
"Dude, how long was I like that?" Dean asks.
"Several hours," Cas answers.
"And you were just holding me up the whole time?"
Cas shrugs, and nods.
"You're supposed to be saving your mojo for important stuff," Dean snaps, annoyed, because Purgatory wears Cas out, and he doesn't like to think about how long they'd survive without the angel's powers. Bleeding for the sigils drains him enough.
"So next time I'll just let you fall?" Cas says, and there's no sarcasm to his tone, just exhaustion.
Dean doesn't know what to say to that, because Cas has got a point, but Dean thinks his annoyance is well-justified. He settles on rolling his eyes. "Just… get some rest yourself, okay? I'll keep watch."
Cas nods, closes his eyes, and lets his chin drop to his chest.
Dean's gaze flits around uneasily. He's not certain if he sees monsters creeping through the dark or if it's his mind playing tricks on him. He shifts nervously and reminds himself that the wards will keep the monsters at bay. He wishes he found himself more convincing.
He looks back at Cas, who's listing dangerously towards one side. He slips a little further-
Dean leans over and his arms shoot out to grab Cas by the lapels of his coat, almost falling out of the tree himself as he catches Cas just in time. Cas jerks awake, and his expression registers momentary shock before settling into tired resignation, as if thinking, of course, why would I be allowed respite now?
Dean sighs wearily, and wishes he had some rope. But Cas really needs to sleep.
"Come here," Dean says. Cas just blinks at him. "C'mon," he repeats, and beckons with his hand.
Cas shifts until he's sitting in the crook of the tree, facing Dean. "Turn around," Dean instructs him. Cas does as he's told. "Lean on me."
Cas settles with his back against Dean's chest, as if there's nothing strange at all about doing so. Which is probably for the best, Dean thinks, keep things straight-forward and hassle-free.
He wraps his arms around Cas to hold him in place, and the angel nods off again almost immediately. His hair is soft against Dean's cheek, but Dean doesn't think about that. He doesn't miss having a fire anymore, because Cas is warm and heavy.
For a moment, Dean thinks that he could fall asleep again, like this. But then something howls, and Dean thinks he hears snarling at the base of the tree. He stays alert until Castiel wakes.