I'm a new BP owner so I'm sure you'll see lots more questions from me. But I have a question about hissing....Do they open their mouth when they hiss? When I have my BP out, Nina, she sounds like she's holding her breath then releasing. She only does it when I get close to her head. She's VERY head shy. I don't think she was handled much and I'm trying to slowly work with her....Any ideas? Will she get over this head shy thing if I keep working at it?