As good as it would be to be able to learn that their bites typically don't hurt much (a papercut is worse) I wouldn't intentionally let the snake tag you. You risk the snake losing teeth and potential infection. Just not worth it. The snakes well being needs to come first.
It's really just about gaining confidence in yourself and learning to learn the animal's body language.
Make slow, calculated movements, with confidence. Avoid going downward with your hand towards the snakes head, don't look like a predator attacking from above.
If you're nervous, the snake will pick up on that, and will in turn be nervous itself.
You'll be fine, just work at a pace that is comfortable for you and your snake. BPs are an extremely docile species and you're just getting acclimated to one another.