Chewing on my hair

New thing DS has started is chewing on my hair. He pulls it and starts chomping down. Then falls asleep. He is a thumb sucker so he holds on to it with his thumb in his mouth and my hair in his hand. Its cute but it hurts when he pulls it and I am stuck waking him up when he falls asleep to get my hair back. Anyone's DC do this? Or do I have the hairy chomper. I don't want him to cough up a hairball