My snake has a rather flighty personality at the moment. He's young (3 months) so I am hoping he changes when he grows but how can I help make him more relaxed and calm?

He is not a shy snake. He has never balled up once, doesn't hide his head. When I come by the enclosure he peeks his head out of the hide to look what's going on. He roams the enclosure at night and is adventurous. So not shy I would say.
But he has a "fight or flight" personality everytime I want to make contact with him. If I move my hand into the tank he starts to get in a defensive position and starts heaving heavily. I mean he takes massive breaths out of fear which I can see because his flanks move heavily. When I begin to touch him he shys away from my touch and if he can he tries to flee. When I finally pick him up he stays in a defensive position for a while. Not curled or balled up but fixiated on me. After a while he begins to move on my hand. And then it's flight time. He moves extremely fast for a BP so I can bearly keep up with holding him. He tries to get of my hands to get anywhere else. Tries to get on my body, nearby furniture ect. It seems he tries anything to get away from my touch .

I know snakes don't enjoy beeing handled but what can I do to make him calm and relaxed like other ball pythons?
I get him out of the enclosure once or twice a week for appr. 15-20 minutes. No improvement so far.