The semi-voluntary shaking of one's legs when one has to urinate badly but doesn't yet have an appropriate opportunity. An effort to stave off the wetting of one's pants.
(pounding on bathroom door) C'mon, dad! I need the bathroom! I'm havin' a pissquake out here, I have to go so bad!
When a woman, or a man, lays down flat on their back with one leg up in the air, at a 90 degree angle. The other partner then takes their foot and sticks it in their asshole, and spins around.
Lets say your at a playground and you see a boyon a stick, you can kind of look at him as a pinsquat.