Old joke, new dynamic.

Overheard in New York | I'm Beginning to Worry You Won't Fit in with My Friends:

"Girl: Why do you fuck a sheep at the edge of a cliff? (waits) So the sheep pushes back.
Guy: I don't get it.
Girl: Do I have to explain sheep-fucking to you?!

--Prince & Mercer

Overheard by: Thiess"