I haven't had my boa hiss at me yet. The clown girl was VERY hissy when she arrived. She did pee in her shipping bag so I can understand the hissy fit (lol). I think I'd be a little worried about my boa hissing when she full grown though. I know a ball python doesn't have much to back up that hiss, but I've seen boa bites and they're a little more messy.

Is your boy going into shed?