A butt guppy happens when you're finished taking a shit but your asshole won't close and is hanging open like a guppy gulping for air.
The other day my starfish squeezed out a girthy turd and it left me with a butt guppy. I think I might be getting ass flu and will have to go home scule.
by Wally Pelech February 15, 2007
1 more definition
See the definition of MUD GUPPIES.
That fag has a fresh load of butt guppies swimming in his man hole.
by Ben October 08, 2004