kiss my ass!
1. A rude exclamation of contempt, disregard, or general disrespect. Kiss my ass, Jerry! You couldn't do a better job fixing this truck if your life depended on it! Some guy tried hitting on me at the bar, so I told him to kiss my ass, and I walked off!
2. A rude refusal to do something someone has requested. You want me to start working on Saturdays, too? Well kiss my ass, I don't need this job!