"Oh my god, dude. Can you not look so pathetic when you're wearing my face please?" And he runs a hand through his hair, because if there's one thing worse than parading around with his face, it's looking like that with it. Use it to strut and get women? He could understand that. But to mop on the bed in front of someone he'd...rather not see him mopey? That's just plain rude.

And Dean might be falling for the whole act. But his face doesn't have the same effect on him, and his hand slides back to wrap around his gun. Maybe Dean's being careful because of the resemblance. It'd be a good angle. One he didn't think they were exactly ready for, but you know, that's a bridge he can tease Dean about when they're done with this.

Nothing like a monster impersonation of your face to let you know how much a guy means to you.