When a man intentionally spins his penis around in circles, moving in a fashion such as a windmill rotates.

Sometimes erroneously called helicoptering, but this is not how helicopter blades move so that's just plain fucking wrong.

When you eat dirt for the first time and leave your family to build a shack in the woods

The act of spinning one's penis around in the fashion of a windmill, usually with the intent of hitting someone in the face. Sometimes done while urinating.

While in 5th on the list - the term originates from the early 90's and should be number 1. It has nothing to do with penises or arms.

Windmilling defined: with regards to thrash metal and extreme music. This definition predates the others- listed here.

Windmilling is the act of a long haired metalhead whipping his/her head around in a 360 degree motion, the hair flies up in the air and around- in the shape of a windmill blade.

Spinning your arms to hit someone with intent to injure.

clutching ones flacid penis at the base, and waving it in a similar motion to that of a windmill

Verb; To whirl one's outstretched arms around in a circular motion, fists clenched, with the intention of hitting something (or someone). This action resembles the spinning blades of a windmill.

Often used in conversation to demonstrate an anger towards a specific subject or entity.