I have had this habit since I was 4. I stopped for a while, and honestly don't know why I quit for a while but I did.
It is bitting my nails. I have it bad. I bite them when there is nothing else to bite, and then start chewing on the back of all my nuckles. Gross I know, but I do it without even thinking about it.
I have tried to stop, but don't notice it untill someone says something or I start bleeding.
Anyone have some suggestions??