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.
I was screwing my wife last night and decided to give her the double piston elbows deep.
by Irishrover18 January 12, 2017
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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.
Man, that piston pump was great. I have never been sucked off so furiously.
by Boozy Barfly November 27, 2006
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the femal version of a dutch ruuder
"gosh, joe gave me a great german piston last night"
by lars fredricksen January 10, 2009
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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."
by Huge Assman November 2, 2017
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A penis, typically one quite virile and DTF.
You know, Gwen Stefani may be pushing 50, but I'd still give her the ham piston.
by Steevve February 26, 2016
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A man who has a piston as a neck

His head can not stop going up and down because of this
“This town ain’t big enough for the both of us, you god darn piston neck

“You fucking piston neck”

“What are ya? A fucking piston neck?!”

“Get off my land you piston neck”

Or if you are a women

“Get your willy out of my face you piston neck”

“Get off my behind, you piston neck lookin retard”

Honourable mentions

Piston Neck Pete
Piston Neck Willy
by TheHungryShoe September 28, 2020
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A man who has a piston as a neck and can’t stop his head from going up and down
by TheHungryShoe September 28, 2020
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