Camera Painting can be done in many ways and is a good way to see how light painting works and reacts with your camera.
The easiest of camera painting is to take your camera in hand, no tripod and set a shutter speed of 1" or 2" a F/5.6 and take a shot pointed at a light source but when taking the shot wave your camera at it instead of trying to keep a steady hand, when finished your reaults will usually be some squiggly lines but sometimes the results can be quite pleasing.
Another well known way of producing camera painting is something called "Camera Toss" and yes it is exactly what it sounds like, same method as before you will set an exposure time of about 1" and as you press your shutter down you throw your camera in to the air spinning it in as many rotations as possible, then which ever light sources are caught in the feild of view will be painted in, but in more of a spinning and confident fashion. I don't have an example of this as i'd never throw my camera in the air and I do know some horror stories of people dropping their cameras, so if you want to see some examples they can be found by googling "Camera Toss" and if you are going to attempt this I suggest using a lot of cushions underneath.
A method of camera painting I do aprove of though are car shots made by mounting your camera on to your car via suction cup, setting of an exposure and driving around. Again this isn't for the faint hearted and precautions must be taken in order to not kill off your camera. Professional suction cups are not cheap, and cheap suction cups are not professional, something to remember if you plan on doing this. I also either trap my camera strap in my bonnet or door when doing this or using a second suction cup as a tether. Danger aside some pretty cool pictures can be made like this one I made below called Terrorists.