Mickey source. Known from the Seinfeld episode "The Revenge".
A Mickey source is a drug dealer.
From the shortened form for "mickey finn."
Used to describe surepticiously slipping someone drugs,
poison, laxative, etc. - usually in one's drink.
Commonly believed to be named after notorious Chicago
pickpocket, thief and bartender - Mickey Finn.
Jerry: Where did you even get a mickey? I can't believe i'm saying mickey!
George: I have a source.
Jerry: You've got a mickey source.