the act of intentionally jamming or destroying another's zipper. Can be done with a string or other fabric, but gum is the most common practice. The most conniving individuals attack their victim while they are wearing the garment, preventing their victim from escaping their garb.
Mom: Jimmy, did you like that bucket of bazooka I bought you?
Jimmy: I sure did mom (thinking: thanks alot for the cheap gum, I liked it as much as I like your fur coat) Mom, why don't you show dad your new fur coat?
Mom: I can't get it on! Dangit Jimmy! You zipper gummed me!