i don't like the thumb in the mouth method of breaking them of biting. they are sensitive to smells. if mine smell somebody different, or something they don't like they crab. they're exotics, they bite. you have to bond on their terms. some come around quick, some don't. my best bonded glider was getting his nails trimmed last week, the vet tech wore gloves (they normally don't) he didn't like the smell and i was holding him and he bit me. he's 9 months OOP and i've been holding him since 3 days OOP. the first time he ever bit. now, he nibbles on occasion when he's grooming me. just be patient. they're scared. offer him licky treats or yogurt drops. they seem to be more receptive if they know they're gonna get treats or goodies from you, not a thumb in the mouth.