The sudden, violent shake of the body during or at the end of a urinating session sometimes resulting in pee hitting the seat or even the floor. The most massive jolts can be achieved in the movie theater bathroom or in dark places you have never been before.
Friend 1: 'Hey guy, I just had the nicest pee jolt at the urinal.
Friend 2: 'I know. I saw your whole body shake. Now let's get back to the flick. I'm sure it has started by now.