For the liquor bottle I used to LED headlamps. The first set up behind the bottle and the second in my hand which, once the shutter was open I outlined the edge of the bottle quickly to get crisp lines.
Same technique used here. First I shined light on the camera and the swung the headlamp around behind the camera to create the white lines you see.
Try this at home with your own camera. First make sure you have your camera on a tripod and set your camera to manual. Use a long enough shutter so you have time to light the object. Next play with different kinds lights as they will come across as different colors. When you have some practice move outdoors and get creative using a combination of natural light and artificial.
Send your light painting pictures to firstname.lastname@example.org and I will post them on the blog.