The booty bounce is generally accomplished with an up and down side to side and just let that fat ass glide motion.
Also gyrating motions in quick sucsession so that the booty it's self is elevated while the hips are in the lowest position, and vica versea. This is more of a booty snap method, however commonly falls into the booty bounce dance header.
"Come on girl, get ur booty bounce on and whip that booty"
"girl knows how to shake dat azz"