I know that most people make tails without mechanisms inside and the way people walk and the lightness of the tail will make it move pretty realistically (hip-shaking FTW!).
But if one wanted to do a snake character without legs (or like a naga), and have a long tail dragging behind in a sinuous fashion, would an internal mechanism be enough to make the tail wiggle? Or would rubber on the bottom help it catch and release the floor in a wiggly motion? Or would it require wheels and some other internal structure to get a snakey movement?
Or, to cover another avenue, is it possible to extend a tail out from a person for a very long distance (let's say, 6 feet/2 meters or more) and have it supportable from the waist of the person without dragging the ground, along with the ability to sway back and forth?