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 2, 2017
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