I haven't been bitten, hissed at, or even had Ajja roll up into a defensive little ball. The most defensive thing she's done is pulled her head back into her hide. Interestingly enough, she only did that in her old tank. I'm pretty sure it had something to do with me approaching her from above. Now that I have a tank with front doors, I'm approaching her on her level. I also handle her every day for at least a few minutes.
A couple of tips -
If your tank opens from the top, put your hand into the tank from the other side and move your hand toward her slowly. If you reach in directly from the top, she'll think you're a predator.
Get her used to your scent. Snakes can identify things by smell. Pre-scenting and braining are perfect examples of this. If you're not going to handle her every day, at least put your hand in the tank so she can smell you.
Watch her tongue. If she's flicking it for a few seconds rather than just one or two quick flicks, she's trying to figure out what you are. You don't smell like food, so what are you.
Snakes don't typically hiss at prey, so I'm pretty confident this is a defensive action as opposed to a feeding response. Just to be on the safe side though -
Don't handle rodents with bare hands. If you're warm and smell like a mouse, you're a mouse.
Don't be the warmest thing in the tank. Rinse your hands with cold water for a minute or two before you go sticking mice in there. Remember the scene in "Predator" where Arnold covers himself in mud to hide his heat signature? Yeah, it's like that.
Hold her food with forceps or hemostats, not your fingers. While there are a few BP's out there that will gently take a mouse without striking or constricting, most will strike, and they're not always accurate.