You've had anal sex and end up with a lot of shit on your penis, you have had a greasynight.
Brain: I heard you had a one night stand last night.
Chad: Yeah, but she was a proper minger, ended up having a greasy night!
Brain: That's fucking gross!
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the US Coast Guard in the area of Southern Florida.