Some snakes are pretty defensive inside their enclosures but will calm down once they're out. Hopefully your critter will grow out of this. I agree with tap training. That's just rubbing the animal with a snake hook before you reach into the enclosure to let them know it's not feeding time, and they're either about to be handled, or you're doing some cage maintenance. I do this with all of my snakes. I have a couple that I still have to remove from their enclosures anytime I'm changing water or spot cleaning because I know they'll tag me.