Snarf bag
As a verb, it is the action of farting into a bag, quickly closing it, then suddenly projecting the air into someone's face.
As a noun, it is the bag which contains said fart.
As a noun, it is the bag which contains said fart.
"Dude, leave me alone or I'll snarf bag you."
"I thought it was my lunch, but it turned out Bill had made it into a snarf bag."
"I thought it was my lunch, but it turned out Bill had made it into a snarf bag."