ream (one's) butt
1. vulgar slang To aggressively and angrily rebuke, criticize, or chastise one, especially for mistake or wrongdoing. I'm going to quit my job—I'm so sick of irate customers coming in and reaming my butt for something I have no control over. The boss reamed my butt for screwing up the accounts like that.
2. vulgar slang To engage in anal sex with one.