When a man inserts his penis into the rectum of another gentleman, the two scrotums (scrota?) come into contact. As the intercourseintensifies, the scrotums will make a distinctive slapping sound. Umm, at least that's what I've heard. I read about it once, honestly.
Buck: So are you and Carl dating or what?
Ned: Nah, we just slappedscrotums a few times.