Handle him calmly and regularly for short spells rather than rarely and for a long time, and skip it entirely right after feeding, which risks a regurgitation, and during a shed when he cannot see properly.
Most kings settle a lot as they grow. Mine buzzed at everything for his first year and now he just comes out and gets on with it. Plenty of hides in there helps more than people expect, because a snake with somewhere to be secure is less defensive about everything else.