To bust ass is to fart. BUT if used with a possesive, it means to work hard.
Also often used with a possessive and immediately followed by an infinitive
I just busted ass and it smells real bad.
You better be busting your ass if you want to finish the job on schedule.
I was busting my ass to finish my homework on time.
The Urban Dictionary Mug
One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.
Buy the mug