My boyfriend and I just got a new python a few weeks ago. He is extremely timid, but seems to be a little more comfortable with my boyfriend and is more curious and exploritive when he is holding him. However every time I go to hold him, he stops moving and being curious and stays very still in my hands. After awhile, he will stretch his jaw (numerous times, it looks like he is having a yawning attack) while I am holding him. This ONLY happens when I hold him. Any ideas why?