It's a insult used on a person who is a pain or useless. The insult reffers to when a male ejaculates on his pants and a stain is left where the semen (or in slang cum fell. Hence the use of "cum") . It's acronym form is CSOTPOS. Used by many teenagers and is not understood by most teaches so it is higly useful.
Jim: DAVE DAVE DAVE!
Dave: Shut up you cum stain on the pants of society
May I have an order of regular degular buttermilk pancakes? Without all the added jazz? Hold the blueberry smiley face, strawberry glaze, chocolate chips and whipped cream.
Usually a male who likes to encourage weight gain in his partner through the consumption of food. Feeders differ from FAs... whilst an FA is attracted to big girls, a feeder gets turned on by making a thin girl fat....or a big girl even bigger.