Definitions by CHOLERA MAN

blue moon 

A sexual act in which blue slurpee, soft drink or food dye is placed into a menstruating vagina. The subsequent period blood which comes forth, along with the blue drink is known as the blue moon, due to the blue colour and the period happening once a month, or moon.

Steve: Shana told me she was on her period last night, so I decided to give her a blue moon.
Jay: Cool digs man.

blue moon by CHOLERA MAN January 2, 2010