one who has no butt formation, a flat saggy ass with no bump or rounded shape.
Look at that bitches phass!
by frombake June 05, 2009
phat + ass = phass. A nice juicy booty. "Junk in the trunk." A sexy butt that is both fat (as in "juicy") and cool/phat (...because it is so hot!).
Shake dat phass girl.
by Seth Romera September 06, 2007