bust (one's) ass(redirected from busts his ass)
bust (one's) ass
rude slang To work very hard. I've been busting my ass studying for this exam, so I really hope I get a good grade. We can't blow off Holly's party—she's been busting her ass cooking and cleaning and getting everything ready for company.
vulgar slang To pass gass; to fart. Who just busted ass? It stinks in here.