The Jack to Jack (Back to Back Jack) Is the attempt to masturbate immediately following a previous orgasm.
I attempted a Jack to Jack but I was to sensitive to continue.
by CharitableNinja February 9, 2009
They are two vine famous teenagers from Nebraska. They also have many good songs like "doing it right" and "flights". Jack Johnson and Jack gilinsky are also very hot.
Girl #1- I love jack and jacks song doing it right
Girl #2- Me too
by I love to turn up August 12, 2014
Person who is kind & wholesome until pushed over the line. Reference to baby JackJack from "The Incredibles" Movie.
Don't keep pushing him. He's going to go Jack-Jack.

Be careful with him. He's got a Jack-Jack personality
by moviedude March 10, 2008
When a guy is jacking off and is interrupted by a second individual who "lends a hand" and finishes the job.Ideally,the interloper could be the wife,girlfriend,a hot maid,or cute neighbor girl. Strangely,the good samaritan could be a sister,grandma,brother or roommate.
I was choking the chicken when my sister's hot friend barged in the bathroom and jack jacked me.
by wolfbait51 May 2, 2011
When one leaves his seat and calls jack jack which ultimately reserves that seat for him when he returns. Jack Jack was created long before Tap Tap and Jack Jack actually over rides all claims to tap tap. Originated in the city of Gig Harbor which was founded way before Tacoma.
When you get up, "Jack Jack".
by Chris Macky December 12, 2007
Having huge muscles (i.e. "jacks")
Greg: "Baby, you think I look swole today?"
Tabitha: "Hell yeah, sugar - you are JACKED!"
by Greg's Girl July 14, 2009