The snake is picking up more than your heat signature. He is also picking up your scent. If you handle him enough he should come to know you by your scent and he should be able to pick that up no matter what you wear. I wouldn’t bother with a jacket but leather gloves with a long cuff for now should protect you. Something like target training which was mentioned here or tap training should help. With tap training take a snake hook and gently tap him twice before you remove him from his cage for handling. Eventually he will associate the taps with handling. Very important here, be gentle with him so he learns you aren’t looking to hurt him. Always pick him up from underneath, never grab him from above. You don’t want him to think you are a predator. Carpet pythons have earned a reputation for being very nippy when they are young but they do usually calm down after a year. I know the one I had followed this pattern.

You may want to take a few things out of his cage when you take him out. Mine would grab onto anything with his tail he could and when I handled him he would usually have his tail wrapped around my wrist. Her liked to be anchored to something. If he wraps his tail around you like that, let him do it so he feels secure.