Lets make a list of things that u'hap't be careful when you handle the portal device.

[iopzx1]

Do not let the kids under age 10 to touch the gun.
Do not attempt to create more than 2 portals.
Do not attempt to lie about the cake.

[1qaz2wsx]

Do not touch the operational end of the device.
Do not look directly at the operational end of the device.
Do not submerge the device in liquid, even partially.

Most importantly, under no circumstances should you-- *static*

[Saikang]

Do no recreate this scenario (http://cache.ohinternet.com/images/c/cd/Portal_Paradox.JPG)

[Ohsneezeme]

Do not attempt to make love to the operational end of the device.

[iopzx1]

Do not attempt to destroy the equipment.

[Fenrixulf]

So yesterday I went back for the Terminal Velocity achievement.
I was falling continuously. I let my Mac just keep going.
I blew up my power strip.
So don't operate the device on two power strips attached to the same plug when all plugs are filled!

[mariobro123587]

Do not feed to dogs expecting to get your dog to shoot portals via barking
Do not steal portal 2 copies from gamestores with it
Do not microwave or the device will implode
Do not feed into a blender
Do not feed into a black hole
Do not impersonate Cave Johnson
Do not turn the device into some sort of A.I.
Please do give this device a job at VALVe
:D

[SpiderGuyVmk]

Do not give the device to mickey mouse.

[AmperWitty]

Do no recreate this scenario (http://cache.ohinternet.com/images/c/cd/Portal_Paradox.JPG)

This would never work. Remember, the portals disappear when a device moves. :3

[iopzx1]

Can I create a portal in my stomach?

[quigonjoe]

Do not attempt to make love to the operational end of the device.

Do not use the device to make love to yourself.

[Raven701]

Do not use it to make mashed potatoes.

[iopzx1]

Do not use other than potatoes to recharge the device.

[Mmmphh]

Do no recreate this scenario (http://cache.ohinternet.com/images/c/cd/Portal_Paradox.JPG)
The orange portal disappears when the platform moves WE HAVE DISCUSSED THIS AT LENGTH

[Lyonidis]

Do not attempt to place the device in an enviroment exceeding 5000 degrees kelvin.

[MagicalTrev]

Do not attempt to use the operational end of this device as a bowl of any kind. It may, however, be used as a shower curtain in temperatures up to 5000 degrees Kelvin.
Do not disassemble device
Do not show the device to your friend(s)
Do not show the device to your cat(s)
Do not show the device to your dog(s)
Do not show the device to your parent(s)
Do not show the device to your neighbor(s)
Do not show the device to your real-estate agent(s)
Do not show the device to the mailman...

[Raven701]

Do not use the device to rob a bank.

[Strider199]

Do not use the device to kill the pedobear, as he cannot be killed.
Do not use the device to try to get the companion cube to speak, as it cannot.