These are the crumbs of food thatmissyour mouth and fall into your crotch. Crotch Crumbs occur most often in movie theatres, dark-lit rooms, and most often when one viciously shovels food into their mouth for reasons unknown.
'Hey, Ron. Can you pass me the popcorn?'
'There's noneleft in the bag but you can have my crotch crumbs'.