A plastic baggy containing a piece of raw liver or jello used for sexual self gratification. origin: prison slang
by George Bourdieu April 22, 2003
A plastic bag filled with jell-o or warm fluid of choice. Once filled it is used to jack-off.
Hey Justin you left you fifi bag at my house.
by Brandon June 23, 2004
A sock or towel used in jacking off to eliminate hand to penis contact. Normally found in bunks in jail cells, boy scout camps, and tour bus bunks. They should always be handled with gloves or a stick due to the nature of the goo they normally contain.
Why are there socks in all the bunks? Don't touch them, they're fi-fi bags!
by twistednick December 28, 2009