when you unzip your pants, but keep the pants buttoned. then you proceed to pull your nut sack out completely through the zipper opening, while keeping the cock in the pants.
"oh dude, what the fuck. that kid just pulled a new england yank!"
"whats that?"
"its when you pull your balls out through your zipper! fuck me man, gross."
Becky: "Gosh Gina, you look great after having the baby!"
Gina: "Thanks! I still might have to yank out a rib to get rid of the rest of this loose skin tho."