The rusty piston
The result of having rough anal sex, and your shaft is covered in feces and blood, giving it that rusty color.
I ran into my ex last night, and the rusty piston was on my bucket list.
Rusty Piston
A sex act involving three men. The first man stands in front while he is penetrated by the second man, and the second man is penetrated by the third man. The second man thrusts between the other two men, thus creating a piston motion.
Bill: Last night, I went home with these two hot guys, and I got between them and we did the rusty piston.
Jeff: Awesome! Wish I could have been there.
Jeff: Awesome! Wish I could have been there.