I can do something weird with my fingers?

For as long as I can remember, I have been able to send "feeling" to my fingertips. When I rub my fingertips together, and with a little effort, I can send really pleasurable feelings to my fingertips. It also works when I rub my fingers through my hair. Strange this is, it only works on my left hand fingers. I have not been able to find an answer to this anywhere. Anybody got at least an idea?