Dean doesn't return the grin. He kicks his boots under the bed and pulls back the covers.

"I mean it," Dean tells him, and there is a little bit of harshness in his tone, if only to counteract the absolute lack of it in Sam's. "I'm getting real tired of it already, and we ain't even headed that way yet."

Not that he expects Sam to listen. Dean will make sure, once they get to the camp, that they stay on separate ends and that Sam is too busy with tasks to complain at him.

"Wake me up in two hours and you can nap until breakfast."

Dean's an asshole, but he's still fair.

More or less.