An epic maneuver in which a man lets his pants and underwear drop to his ankles, lifts his shirt up to armpit level, and urinates, much in the manner of a 4 year old trying to use a urinal. Usually executed while intoxicated. Occasionally performed in tandem by a group, no homo.
Since many guys did this at urinals when they were kindergarten age, the act of doing this is often referred to as "bringing it back".
"Guys, I have to pee. I'm gonna bring back the bare ass piss."
"Joel, I heard you brought back the bare ass piss the other night."
"Feels good, man."
BASF stands for Bare Ass Shrapnel Fart. To do a proper BASF one must drop one's drawers and sit, bare ass, on a hardwood floor and then rip a monster fart. The vibration of the buttcheeks against the hardwood creates a natural reverb chamber/amplifier resulting in a thunderous cacophony akin to a gunning a chainsaw while firing an M-16.
Joe's BASF (Bare Ass Shrapnel Fart) blew a hole through the parquet and now the Celtics have to play home games at Sacred Heart until they fix it.