1 definition by learntoswim

A precursor to the hard on, a cousin of the half schaff, and little brother to the half wood, a sudden rush of blood to the penis resulting from visual or aural stimuli, whether sexual or otherwise. Usually felt and identified when the male member first comes into contact with the fabric of the pants; often concealable with proper use of misdirection and hand gestures.
Bro: Dude, when your mom called my name to get my attention the other day, the sound of her voice made me pop a part on. I had to keep scratching my nose so she wouldn't notice the extra weight in my package.

Bro's bro: Dude, you're a douche.
by learntoswim August 27, 2009
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