The Spooey Bag is closely related to the term "Spooey Rag". That of course is the rag you use to wipe her twat once you unload into the meat curtians.
Dude1: "Hey dude... did you get to hit the Spooey Bag last night."
Dude2:"Yeah bro... I left that shit all tattered. I think my balls bruised her asshole I hit it so hard."
Example2: "Hey dude... are the Spooey Bags coming to the game with us tonight?