Can be an obsessive type coping mechanism from something bothering him he doesn't know how to manage(physical or psychological) or possibly a form of seizure. I'd video his licking and take the vid and him to the vet for check up. Any change in behavior like that I usually take my dog in for an exam just to be sure.
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |