bust one’s ass to do something

bust (one’s) ass (to do something)

and break (one’s) balls (to do something) and bust (one’s) butt (to do something) and bust (one’s) nuts (to do something)
tv. to work very hard to do something; to work very hard at something. (Usually objectionable.) You get down there and bust your ass to get the job done right! You hear me? I busted my butt to please her, and what do I get?
See also: ass, bust