Some days I will handle mine and he will be a blob just barely hanging on where I have to hold him with two hands. Sometimes he will be the derpiest spaz on the planet launching himself into an upside down slide and try and climb all over everything. Every so often he likes to squeeze the life out of me or at least pretend he is.
None of these times is he showing any signs of stress or aggression. He simply has a mood that day and I have to say the days where he likes to wrap himself around my neck and squeeze for all his worth are both a great massage and a terrible way to slowly die.
So not to worry too much. It could be a sense of not being secure and they tend to wrap around the arm like that or it could just be that they want to do it like mine will.
You did say "which makes me a little nervous about handling". Snakes are really able to sense your tension. You need to learn trust and give trust. The best way to do this is to routinely handle your snake and above all else stay calm. The worst bite from a BP is nothing at all.
Here is what I do. I feed my snake every week around the same time. After feeding I avoid handling for 2 days to allow him to digest and relax. I then take him out 2-3 times a week and that is it. I try and avoid handling a few days before feeding as well so he has a chance to mellow out before feeding day and because he is regular as clockwork and I know that come 5-6 days after feeding he is about to poop.
Now when he turns pink belly and gets about in blue, I will avoid handling him at all until he sheds. Other than that, I try and get to him weekly.
After 6 years I don't have a snake that begs to come out of the cage to be handled but I do have one that is perfectly at ease being handled and he does not strike or ball when I do so.