lose your rag
lose (one's) rag
slang To become extremely upset or angry, usually unexpectedly. Primarily heard in UK, Australia. I'd had such a rough day at work that I lost my rag when my brother started teasing me once I got home.
lose your ragBRITISH, INFORMAL
If you lose your rag, you suddenly lose your temper with someone and get very angry. You can imagine just how easy it would be to lose your rag in that situation. Eventually Melvin lost his rag and hit the guy.
lose your raglose your temper. informal
1998 New Scientist In boxing as in medieval theology, anger is a sin. Lose your rag and you are likely to lose the match.