dont get your panties in a bunch

Dont get your panties in a bunch is another way of telling someone not to get upset or flustered. Like many other idioms of the same meaning, dont get your panties in a bunch (or dont get your panties in a twist) is a way of telling someone they are becoming agitated for no reason and should just calm down and relax about the situation. It is a sarcastic warning of not becoming upset over the current situation.