a past time (usually played in sober living houses) that involves inserting a 2 liter bottle full of warm water into your ass and then exerting pressure to eject the water as far as possible.
When he spit the winkle a chunk of poo hit the dog in the head. Then the dog ate it
When someone sticks a garden hose up their ass & fills up their intestines with water, walks like a duck to their nearby target, and launches the high pressure stream of water out of their ass...ideally hitting someone in the face.
It was deemed that no example is needed for the term Spit the Winkle.