Pimmy Shimmy

The act of a man waggling his penis in an up and down fashion using his pants/shorts so he can shake off the last bit of pee that might be inside or stuck to the tip. Commonly used after urination, but can also be a strange way of getting erect.

Blake: Yo Travis, do you not pimmy shimmy after you piss?

Travis: No man, that's just weird!