This refers to a gay sausagefest hangout in as in referring to an upside down barstool for their ass.
Yo watchout for that happy stool, there is some gay shizzle happening in that hizzle.
by Rob A.K.A. Blackrob April 10, 2003
A turd in the shape of a smiley face sitting in the bottom of the toilet bowl
"Honey, you gotta come and see my happy stool!"
by *xJennx* April 10, 2003