1 definition by TheBassist99999

(v): to stroke one's shaft until semen is ejaculated from the penis. While riding an effing bike. Seriously.
Happens sometimes at Colorado College...
Possibly the most perverted act one could ever commit.
"Did you see that sick pedophile masterbiking while he passed by all of those eight year old children? He just loves to masterbike; it's his favorite pastime."
by TheBassist99999 September 3, 2009
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