I think my ball hissed at me!

[Lolo76]

All snakes do have the tendency to hiss, but BPs less frequently than some species (in my experiences). I do have one, my het Albino Rosalind, who hisses like a deflating tire almost any time I touch her... it's all a bluff, though, and she's never tried to bite me! She is just a shy girl, and thinks that sound will scare away the "big mean monster" that is me. I wouldn't worry much about it, and just insist on holding him regularly - it will eventually make him more comfortable with you. Oh, and is he going into shed? Most of my snakes get cranky during a shed, and that's how I got 2 of my 3 total bites.

Edit: I see he's not in a shed cycle, so he must have just been feeling shy... and as somebody else said, their bites aren't really a big deal anyway.