Our gliders sometimes will find a spot they think needs grooming. they will
start to chew then start to dig with their teeth. it will quickly start to hurt
as they are doing their duties of grooming me. they will slowly cut my skin and
draw blood. so I will just gently push them away. if they return to continue
the grooming, i gently push them away again.
yours could be grooming or just thinking they found something to eat, a smell
or taste. I would start by just moving them or him away from that spot or maybe
offer them a treat.
If I forget to wear my socks, the feet are a favorite. they will lick and chew
at old skin and can be painful so I move them away or put on socks.