When a man or woman puts both of there fists inside a butthole or vagina and moves in conjunction While one fist moves down the other goes up. Like a engine piston.
by Irishrover18 January 12, 2017
Slang referring to an aggressive, furious, rapid act of fellatio. The piston pump receives its name from the rapid head movement exhibited by the provider of the fellatio, which is said to resemble the action of a moving piston. This is also referred to as the jackhammer. The piston pump is much sought after in the world of fellatio and should be received with grace and humility.
by Boozy Barfly November 27, 2006
by lars fredricksen January 10, 2009
How to describe a person that has been fucked so hard or for so long that their body flops around like puppet with every pounding thrust.
About 3-hours into the surprise gangbang party my wife was a pouncing bouncing spit roasted piston puppet. I warned her about trying to party too hard in the beginning but she's loves looking like a cock pierced voodoo doll within the 1st hour.
by Crumpedout_27 April 27, 2019
When your going anal with a bitch and she shits while your dicks in her ass forcing it back out like a piston.
by Donkeykong2128 May 29, 2015
by Steevve February 26, 2016
Yet another slang term for penis. It is meant to be humorous and not as offensive as some other slang terms.
Fred : "Dude, I thought Darcy was leaving you."
John : "What can I say? She can't get enough of my butter piston."
John : "What can I say? She can't get enough of my butter piston."
by Huge Assman November 02, 2017