The sexual act in which two partners have logs of feces halfway out of their assholes, to the point where they are able to hang free but not break off. The partners then proceed to touch asses together and move them back and forth in a swift, rapid motion, thereby 'clapping' each turd together, resulting in a violent yet beautiful splatter of each partner's natural waste.
"Man, I tried scat clapping the other day. What a mess. It was pretty intense though."