A possum belly (aka possibility) is a storage area in the bottom of a trailer, house trailer, ride trailer or transport trailer accessible from the outside. It can vary in size from being as small as a cupboard to as big or bigger than a walk in closet. It origin is unknown but it is typically used by carnies.
Stop having sex in the possum belly and get back to work!
Take your weed plants out of my possibility before the boss yells at me!
Your rides possum belly looks worse than the donnicker after busy Saturday, who taught you how to coil cables?