Know the range of your cartridge.
Most C2 cartridges have a 15 foot range. If your attacker is further away than that, your taser will be ineffective. Make sure you know exactly what 15 feet looks like!
Use the flash light feature.
A C2 looks like a flashlight anyway, so it is relatively inconspicuous to use it as a flashlight. This will ensure your C2 is immediately available if you ever need it.
Aim for "center of mass."
This is where police officers are trained to shoot. Effectively, you aim for the largest part of the body you can see. In the vast majority of cases, this would be the torso. When you accurately hit the torso, this is an amazingly effective tool. For this reason, I believe the optional laser sight is a "must have" on the C2.
Fire your Taser.
When you fire your C2, you will hear a distinct "pop." At this point, your taser fires two darts into the aggressor and almost instantly begins sending electrical impulses down the two wires, immediately incapacitating your target.
What to Expect.
You can expect your Taser to make sort of "tapping" noise. Your attacker will most likely go rigid and fall to the ground while making a sound similar to "ARRRRGGGGG." (At least that's how I sounded during certification.)
Hit the Bricks!
Your Taser will continue to incapacitate your attacker for 30 seconds, after which, he will be immediately and completely recovered. You must use this time to get away and summon help. Lay your Taser on the ground and beat a hasty retreat while calling for help. Don't worry, Taser International will replace your C2 free of charge with a police report.