Gastank

To urinate in a persons rectal cavity. Can be followed by "siphoning" in which a hoselike object is used to siphon out the urine.

After John gastanked Jill, he proceded to siphon out the urine with a straw.

by Kyle J. November 10, 2004

Gastank

You are stuck in a gastank when someone cuts a fart in an enclosed area, like a car or an elevator.

The drive to the beach sucked because Hugh had some serious beer farts and it was raining. I couldn't open my window and my eyes were watering in that gastank.

by Omphalos October 26, 2012

GasTank

A reference to one's bottom

Ergh, Jesus christ Gary, shut yer GasTank will ya!

by ShugaDunkerton October 19, 2014