1. Taken from the classic movie, Clerks, a gizz mopper is an employee of janitorial status who works at a nudie booth. When satisfied customers blow their loads on the glass... this really doesn't require much more explanation.
the jizz moppers job is to clean it up after each guy shoots a load, cause practically everyone does it right on the glass. I dont know if youve noticed but cum stains if you dont clean it up right away