It's the accidentally attended an angel orgy. Dean was okay at first, what with the beer and snacks and all, and could kind of ignore the shirts coming off (it was a hot day! it's not his fault), so when the pants started coming off, he was right in the middle of it and couldn't get to an exit -- that's his story, and he's sticking to it!

lol. Castiel translating violent threats deadpan would be hilarious. And also trying to disuade attempts to flirt with Sam by males who really haven't figured out that Sam's also male -- Sam's so tall she must be female!