I face the same issue with my younger one, Tia. Amazons seem to enjoy wrestling with their owner's hands and my other one, Ori, seems to enjoy that a lot. Sometimes I would put the palm of my one hand rolled up in a cup on her head while scratching her fervently on her neck and she would fall on her back in my rolled-up palm and would start softly gnawing my fingers.
This is something I definitely cannot do with Tia. She will step up, as she and her sisters have been trained to do, but when she starts gnawing my fingers, she quickly resorts to aggressive, painful bites. In those moments, I try to stop her with a resolute "No!" and a raised index finger, but she often will not stop unless I force her off my hand by putting her on the aviary, or shake it to make her lose balance a little or fly away. When that happens, I turn my back at her. She would sometimes try to come back, but I put her back on the aviary and ignore her for a couple of minutes.
She is also more often the one to nib me on the neck if I pick up something she does not like, but that is something I have come to expect and try to avoid such situations if possible.
Tia has been a puzzle to me, frankly. She lets herself get petted on the neck, on the chin, or the cheeks, when the mood strikes her, and she is usually quite docile, too. I reckon she does not like the hands because I had to forcefully put her in the aviary after chasing her for a bit.
I regret that, I realize it was a mistake.
I reckon I may have to keep her off my hands until she becomes more comfortable with them again.
