Definitions by Ralph Cox and Steve Janaszak

Windmill 

swinging your penis around in a circular motion.

Janaszak: "Coxy what are ya doin in there?"
Cox: "Shut up Janny I'm doin the Windmill! You're welcome to join."
Janaszak: "Be right with ya"

Windmill by Ralph Cox and Steve Janaszak May 8, 2014