Pull the stick out of your ass

It means that the target is in a bad mood or in unnecessary distress, and you are implying this with the notion of them having a stick in their anal cavity, which, of course, is very painful and would definately cause a rather pissy mood. It's a way of telling them to STFU. However, this phrase is not recommended around people who constantly make Yo Mama jokes. A similar thing to say would be telling them this with the Sandy Vagina phrase.