A penis that looks average until it is aroused and then erects to a size well above the norm.
Andrew: Yes, my penis looks only about an inch long when it is soft.

Slampiece: Well I must admit, your Jack in a Box was a nice surprise!
by Quagmire517 September 9, 2011
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To masterbate at work in a cubical or perimeter guard kiosk.
The officer was caught jack in the boxing in his guard kiosk.
by Got caught January 16, 2014
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A name of the action described as such: when a girl, who is so hot that when she unzips your pants to give you blow your load before she touches you.

When the timing is perfect and she gets hit in the face with your sperm before she even touches you - she received a jack in the box.
Dave: "dude that girl I left with was so hot, she got the jack in the box"
Steve: " really in the grill?"
Dave: "you know it"
by Joe Shabadu March 25, 2008
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A stand-in name for any company you have ever worked for. Use this to avoid any awkward references to a previous employer (similarly, you should avoid mentioning the name of previous boyfriends/girlfriends while your current partner is present).

This meme started in 2014 as an inside joke between two data scientists, Steve and Spencer, who are working for a major video game company in Boulder, CO. It is a reference to their colleague, Adam, who actually worked at Jack in the Box corporate headquarters (and speaks often of it fondly).

Since then it has spread to studios in Los Angeles, Seattle, and the UK. There are first-hand reports that the meme has also been spotted in the wild at Microsoft.
Hey guys, at Jack in the Box we used python.
by Truegen August 7, 2015
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When your fucking a girl (usually doggy style) and your boy is in the closet jerking off then he runs out and busts a nut on her face.
Yo man this Bitch gave me the Kangaroo so I got her with a Jack in the Box.
by DC April 11, 2004
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While texting, you reply to their messages so quickly, that you scare away potential romantic partners.
He replies so fast, he’s like a jack-in-the-box.
by QuimpGod69 July 15, 2020
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