Yep that is normal behavior, at least in my experience. My bp loves to explore and rarely sits completely still in peoples hands. If/when you do you do place your bp around your neck just remember that you are a living moving tree to them and so when they do grip on they aren't trying to strangle you, they just are holding on. The good thing about a bp is that, if the squeezing does get uncomfortable you have the ability to move them off, GENTLY, unlike a larger snake, which probably shouldn't be wrapped around your neck in the first place. As stated above as you handle your bp it will slowly grow to trust you more, and in my experience grip less tightly.
Have a great time with your little friend!