Plumber's Slouch
The Plumber's Slouch occurs when someone's pants and shirt separate, usually when a person is bent over... giving everyone a view of the person's butt crack... but Plumber's Slouch allows you to refer to the situation without being overly graphic.
Please wear a longer shirt under your sweater, so you can avoid Plumber's Slouch every time you bend over. No one wants to see that!