A codenamed elevator that needs a key to be ridden upon. People who call an elevator "Grey Moose" are usually not supposed to be riding the elevator hence the codename grey moose.
Dude Uno: Hurry up i got the key to the grey moose!
Dude Dos: Oh shit! let me get on with you!
When you try to hook up with highclass broad and cant afford grey goose, you aquire an empty bottle of greygoose and fill it with mccormick's vodka. (works with any cheap vodka)
hey bro those snobby broads are coming over throw the greymoose in the freezer!