Farting around. Foaming at the mouth. Coughing up a lung. Have you ever heard these crazy expressions? People use them even when no one's really farting, dealing with a foamy face, or losing a lung. That's because these sayings are idioms-phrases that mean something different than what the words in them actually say. But don't let idioms make you sweat blood. Let's explore a variety of gross idioms and figure out what people really mean when they use them.