Sam paused from what he was doing, looking up at Dean. He snorted, a little distracted by Dean in those clothes. It's not that they looked bad or anything... they looked good on him. He just wasn't used to seeing Dean dressed up like that.

But it was hard to linger with the amusement at the question. Not like he was easy about that, going after humans, but... "I'm not letting you do it alone, Dean."

The idea of them getting the upper hand with Dean, draining him... it was enough to get him onboard. Besides, the fact that they were draining vampires for blood? Too skeevy to just ignore.