1 definition by Lifewithaknife

Top Definition
When a male has fapped so much, that one arm is bigger than the other one.
Guy 1 "Dude how did Daniel get so buff?"

Guy 2 "Look at his arm."

Guy 2 "It's because he tones his Masturbation Muscle."

Daniel "No! I just workout."
by Lifewithaknife October 31, 2011

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