The act of pleasuring oneself to the words of another party's flirtatious phone call, or other form of message, without that party being aware of one's pleasure.
J: "I really don't see the point in fumping!"
A: "I heard Kiki was fumped by Cedric the other day. Poor her."
J: "What an asshole. But what did you expect from a frat boy such as him..."
The act of flumping involves stuffing a flump marshmallow inside a volunteers bum 'ole and then proceeding to suck it out as romantically possible. Considered to be the most erotic and tasty act of sex.