Piston Fisting 

A double fisting that incorporates both anal and vaginal penetration. Fists are then pumped in and out in manner similar to that of pistons in a engine.

I gave that filthy sow the piston fisting of her life.

Piston Fisting by josh1234 January 4, 2006

Piston Fisting 

The art of shoving one whole fist in a girl's arse and the other in her vagina and ramming them in and out alternately (like a piston system)

I was piston fisting her til she blead

Piston Fisting by Tha BIG Daddy H July 26, 2009

fistin piston

a fistin piston is a very delicate process that can be done on any girl who is down for some serious pain and pleasure. there are two different ways of going about the fistin piston.

1: having a girl lay in front of you, while fisting her sideways sloppy joe with an in and out motion with both hands, similar to the pistons in a motor. this motion is incredibly similar to throwing bows

2: the second process, ironically called number two is similar to process one although the fisting is done with one hand going in the slimy hatchet wound, and one hand going in the baloon knot. aka: {5 in the pink 5 in the stink]

it was bad enough danielle's mom walked in on us, i was giving her a fistin piston, there was bloood on the walls and everything. i felt bad so i helped her find the random pieces of sloppy sausage wallet that were strewn across the rug.

fistin piston by ed harris September 18, 2005