This is fairly recent (I believe), but I thought it would be interesting for everyone else to know.

What this essentially does, is in game modes like Demolition and Search and Destroy where you can plant a bomb, you can run around with the laptop without planting.

Tutorial:
1) Put an assault shield on your class. (This is required for now, I may look into the glitch and see if you can do it without the assault shield)

2) When you can go plant the bomb, walk over to it with your primary (assault shield) out.

3) Start to plant and when the circle hits half way, crouch and knife while crouching.
If this is done correctly, you will see text appear and your player will lay down with the laptop out.

*IMPORTANT* Make sure whatever button is pressed to plant is still being held down!

4) Continue to hold X or the equivalent on other platforms and now you can stand up and walk around!

You may want to practice in a private match

Enjoy!

Pros/How it's useful:
-Something funny to do in game.
-Would be a pretty epic killcam ;P
-Funny and creative way to troll.

Con:
-It restricts you to holding a bomb, as soon as you need to kill the enemy team, your at a disadvantage.
-If you climb or press certain buttons, including releasing X, you will close the laptop.

If you have any other tutorials you would like to see, just message me!