I've been able to stop my boa by putting my hand in front of her face, and the only thing she does is give me a "you're ****ing WEIRD" look when I do it, or push at my hand with her nose until she give up and goes another way. I don't know if that's because she's older and has had time to mellow out, or if previous owners did that with her and she's used to it or what. I wouldn't recommend doing it with a boa you don't really know if you're not ready to get tagged though.