Sometimes during masturbation, a pocket of air becomes trapped under the foreskin. Upon pulling back the foreskin the air is released creating a sound similar to a fart.
Man: "Pfft."
Woman: Did you just fart honey?
Man: No, that was a bell fart. You wouldn't have sex with me tonight, so I'm relieving myself.
by Kelfaur February 1, 2014
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