Similar to "prairie-dogging": When a turd leaves it's nest, sees it's shadow, and runs back in. This is a precursor to the "turtle-head", and should not be taken lightly. Short yet expedited steps in the direction of the nearest toilet facility are recommended immediately. A post-evac check of the surrounding areas will signal a possible 6 week extension of gastrointestinal discomfort.

When you have to poop really bad, but you are forced to hold it, and you feel like you are about to poop yourself.