Purple Milk is a term used to describe a large all male sex orgy.

Purple Milk events are often organized by advertising a concert for the band "Purple Milk" but if you were to go to the event you would be more likely to receive a rusty trumpet than a music treat !
Hey guys tell Jimmy to stick up some posters for a huge Purple Milk next week
by Jack Tuesday January 3, 2008
Get the Purple Milk mug.