A sex position when you hold a girl upside down and spread her legs to resemble the handles of a jackhammer while doing this you pound your penis in the girls vagina causing her to go up and down like a jackhammer
Created after the orginal thought of the drill, the jackhammer takes speed and power in order to work. Start by creating a fist. Then, get into a stance that will allow maximum power and speed. Arch your back forward and thrust your fist through your other hand, in some what of a punching motion. Try to build up speed. That is the secret of the Jackhammer. Kids, don't try this with grandma in the room.
"Your Drill's got nothing on my Jackhammer"
"Why don't we just stick the Jackhammer in with all the other tool techniques."
"I hope you're proud. Damn you drill and Jackhammer!"