Leigh always goes there

My friend Leigh has the dirtiest mouth. I can't take her anywhere. Just when you think you're having normal, friendly banter, cursing and shredding each other politely, she goes and pulls a whammy like this:

Me: Oh you're just sooo busy. You're soo busy. You realize you're just sticking it to the man, right?

Leigh: Why don't you go lick a cunt. Then you'll be busy too.