acronym for: Fiery Anal-Piss Symdrome.
known in some circles as the most god awful form of diarrhea.

when you blow out your bowels in such a way it resembles piss coming from your asshole. there are usually no chunks present when you have the F.A.P.S., but there is an extreme burning sensation when finished.
I think i ate a bad clam or something yesterday, i can't get off the pot because of the F.A.P.S.
by tony August 12, 2004
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