Two-year old skittish ball python

[Bogertophis]

Try picking him up after he eats when he’s calmer and let him explore your hands. Using a hook to encourage him out instead of reaching in can help, too.

To the first part of this, I disagree. First, you don't want to interfere with, much less cause, a regurgitation of a meal by handling too soon after eating. (Maybe that's not exactly what you meant, but for the sake of clarity & preventing problems, I have to assume.) But more to the point, for many snakes, they'll still be in "feed mode" & ready to misinterpret your hand (or anything else) as more incoming prey. Oops! ("Feed mode" can last hours or even days, depending on snake's own personality.)

Using a hook is an option, if you're that worried about a bite, though most BPs don't warrant "tap training". Whether you use your hand, a snake-hook, or something else (like the empty sleeve of your shirt or the cardboard roll from paper towels) snakes generally learn the touch that signals "I'm about to be picked up by that big harmless warm thing over there." & accept handling.

Note that it also depends on the species of snake you're working with. I find that unlike boas & pythons, rat (& corn) snakes generally recognize my scent quite easily. The size of the snake's teeth can also determine how much "bite prevention" you're comfortable with. (Large boas have much bigger teeth than rat snakes & therefore see a lot more "tap training" )