Bust your ass - Idioms by The Free Dictionary
bust your 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.
bust your ass try very hard to do something.
bust your ˈass/ˈballs/ˈbutt/ˈhump (American English, taboo, slang) make a very great effort: I bust my ass to get that job. ♢ I’ve been busting my hump for the last week trying to get the project finished.