Thanks for your replies. I used to do it when playing cards, bored, impatient and still do it when I'm thinking. It is semi-concious. I control it, but not like I think "oh I'll jiggle my leg now. It was always my right leg, which is the side my PD is dominant on. It just made me feel better. I always thought it was a way of releasing pent up nervous energy. All the leg jigglers I know are married to non-leg jigglers, and their spouse's usually find it annoying. Isn't life interesting?