A rude insult or a flirty compliment depending on the context.
Rude Insult: A person so worthless they are too undeserving to eat pussy and is only permittable to taste the air excreted from the vagina.
Flirty Compliment: Someone you like so much that you don't mind that they see the vulnerable side of you, someone you would be okay queefing into their mouth.
Him: "Shut up you are such a Queef Muncher!"
Him 2: "Ouch!"
Him: "You taste great!"
Her: "Haha you are such a Queef Muncher 😉"
While most people shy away from a woman's vaginal expulsions of gas, my friendPhilip can think of nothing less enjoyable than munching away on queefs; he's a fucking queefmuncher