A boner that curves upward, resembling an upturned banana. Legend has it it's especially good at stimulating the elusive g-spot on the female anatomy, but I wouldn't know because I have a straight boner.
by Darren Key June 26, 2005
When a male has such a large erection, (Particularly during sex), that his penis begins to curve upward to resemble the shape of a banana.
by SE123 March 10, 2014