When a girl that has a flabby ass uses tight jeans to hold the ass in place. You can still tell as it is trashy. Like a garbage bag overflowing, if the jeans ever exploded, you would have a mess. Abbreviated as GBA
Matt: Jeff do you think my ex-girlfriend is hot?
Jeff: Not really.
Matt: Why the f**k not?
Jeff: She has a major case of garbage bag ass.
Well, I was chatting with my friend Scuba7Hoods and I ripped a nasty fart. It sounded like someone had ripped open a loose flopping paper bag thus I coined the phrase and it caught on. I mean now the whole world likes to rip a bag of ass!
Goodespeler ripped a bag of ass this morning while he was bending over to tie his shoe.