how much a girl's ass jiggles when you slap it.
when it doesn't jiggle it can either be not sexy or sexy depending on the guy
when it does jiggle a little that is really sexy and alotta guys like it.
when it jiggles too much thats just......
dude 1: oh dude i slapped my girl's ass and it didn't jiggle at all. she had a low jiggle factor.
dude 2:is that good or bad?
dude 1: i say its bad! i want that ass to jiggle.