butthole drums 

The slapping, whether by accident or design, of any part of the male genitalia on the anus during sexual relations.

1. Yeah, I played the butthole drums on my ol' lady last night, just so's she'd know what was coming.(indicative of anal intercourse)
2. I played the butthole drums with my nutsack last night. (As in the missionary position)

butthole drums by Ken Wheeler April 14, 2009