Stealth Jack

The use of the word is done so in which to trick someone during the game of Bullshit / Cheat / I Doubt It, not just restricted to jacks but to your personal favourite card. This is used to make someone think you are bullshitting, or to people that know you more well, make them think you are in fact not bullshitting.

You: Yeah I place down a stealth jack...I mean a 7
Silly Billy: Oh mate that defo bullshit you so put down a jack
You: nah m9 #dealwithit

or

You: Stealth jac...I mean a 6
People: You do that all the time now we know it is a 6
You: *gets a free pass for lying*

Stealth Jack

Jacking off in a public place/room with some people without anyone noticing and busting a nut.

A: I managed to pull off a stealth jack in a room with 3 people.
B: That's fucking disgusting but also pretty impressive.