Jump n Jack 

When a couple is having sex with the girl on top unprotected and he cannot pull out being that he is on the bottom. She will proceed to jump or move as quickly as she can off of his penis and jack him off. Hopefully to prevent pregnancy.

I was about to cum, so i warned her, and she Jump n jack 'ed me off!

Jump n Jack by louhoo December 26, 2009

scat-jack 

"Freaky Stuff" that a guy & his wife do on special occasions....like anniversaries, birthday's, president's day, etc...

On Dominic's Birthday, his wife treated him to a very special, fun-filled night of scat-jack!

scat-jack by John - Louisiana May 16, 2007

Elbow Jack 

The Elbow Jack is the latest in jerking off technology. It is proven to be the most pleasureable method of beating your meat.

Requirments, - Penis - Elbow - lubricants

In order to do the Elbow Jack your elbow must be flexible.

Step One: Place erect penis between forearm and bicep.

Step Two: Apply Lubricant

Step Three: Slowly start up and down motion. Until you have came.

Warning If jerking to fast, rug burn may occur.

Invented by: Paul & J.D Sanghera.

I love the creators of the Elbow Jack.

Elbow Jack by Big Black Paul June 8, 2009

The Matt Jack game 

A game involving a Matt Jacker and several of your friends.
the aim is to get further away than your friends from the Matt Jack whilst giving clues to the Matt Jacker that you are getting away

Person 1: I'm winning The Matt Jack game!

Person 2: fuck you, oh shit! here comes the Matt Jack!

Matt Jacker: can i play?

The Matt Jack game by Roo Barb March 18, 2009

Pull a jack 

To pull a jack is to either completely embarrass yourself in a situation that shouldn’t have occurred, or to simply say something so irrelevant or stupid that it resembles something a jack would do

“That literally had nothing to do with anything don’t pull a jack

Pull a jack by creator657 June 2, 2018

Captain Jack 

Common in fan fiction, a "Captain Jack" is a fictional character who is a projection of the author's wish-fulfillment to the extent that it spoils the story. From the TV series "Torchwood"; Captain Jack Harkness is the immortal and flamboyantly omnisexual projection of Russell T. Davis, an aging gay atheist

You'd better re-write that chapter. Brian is turning into a Captain Jack

Captain Jack by Hastur T. Fannon April 18, 2007

lumber jack

Lumber Jacking is when you eat something (no matter the size) in a single bite.

I bet you twenty dollars you can't lumber jack that steak!

lumber jack by Alex Otto November 20, 2007