A sexual fetish in which the participants wear clown makeup, or do anything clown-like during sex. Referred to in Mystery Science Theater 3000, while watching the film "Here Comes the Circus." There have also been specialized porn films dedicated to this fetish.
Guy: Hey baby, wanna do it clownstyle tonight?
Girl: Sure, as long as I get to blow up a condom and make it into a penguin!
Guy: That's so hot.