a WEENURR
this is my pork piston. it goes in your cumbustion chamber.
n. adj. A greasy piston is a person that indulges in activity of the homosexual persuasion. Greasy coming from the chocolatey brown color of shit, and piston from the penis and it's motion in and out of another man's rectum.
I think you are a greasy piston.
A group sex act in which three people who possess phalluses simultaneously penetrate the orifices of one other person.
Three members of the college football team showed the Captain of the cheer leading squad how a three piston engine worked.