Maasai jumping-jack
You bounce like a fool with your junk squeezed between your legs. It’s the worst kind of wank ever. People do it when they’re too lazy to use their hands but still too proud to admit it.
My neighbor does it every morning. I swear the whole street can hear him.
At the bar, my friend did it in front of the bartender. He got kicked out.
I did it on the bus. The kids thought I was a lunatic.