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The unfortunate and highly painful feeling that builds in the posterior when one sits in a rowing shell for too long. The sensation is similar to sitting on a bed of needles or having your ass tasered. Possibly the most agonizing pain known to humankind after the 2k. One can also experience boat butt by spending too much time on an erg.
Rower: Dude, three hours on the water gave me the worst case of boat butt.
by Splunkin' April 18, 2010