When you eat a large volume food that leaves crumbs, such as an entire bag of cookies. By the time you finish your session of gluttony, you have crumbs all over your chest, stomach, and lap, and you have to unhook your belt and pop the button open on your jeans.
This usually occurs on the couch, in the car, on a plane, or anywhere where you are eating without a table and remaining stationary.
Jack Nicholson was crumbs undone after he ate three chocolate croissants while flying first class to London.
Freako sex game that involves: 1 loaf of bread, 2 bum holes, and a good aim. One must stretch open their bumhole while the other one tries to insert a small piece of bread into the hole from whatever distance.
Evan: Are you up for some fun tonight sweetheart?
Melissa: Oh yes, let's play crumbs in bums!