"You Wanna Get Down On This Protein Shake?"

Is this new?  Male reproductive organs are being called protein shakes?  I really need to start checking into the Urban Dictionary (*UPDATE* I checked and found out it refers to the reproductive fluid, at which point I slapped my forehead and went "Oh yeah, huh.") more often.  I will most definitely have to insert that term into some conversation, somehow...perhaps when I'm sitting at the Spotlight on Sunday or Saturday morning, flipping through the hooker section of Frontiers.  I'll spot one I like and exclaim, "I wanna get down on his protein shake!"  "Bro!"