I've used one in a fairly limited waywith Nibbles - set to "mist" - and it worked. It was the *only* thingthat reached her regarding her giving me constant hard nips(along with a loud "No," foot-stomping, etc.). With otherbad/potentially dangerous behaviors (trying to eat carpet, forexample), "No!" + clapping and footstomping (and other things to do)has been enough.
but the nipping was persistent and quite different. I worked with herfor many weeks re. gently pressing her head and shoulders to the floorfor a second or two after she did it, then praising her to the highheavens when she decided to nose-bump or lick. She understood, butstill didn't stop nipping.
I got so tired of hard chomps and was running out of patience - calledthe director of the shelter where I got her and she suggested mistingher. At first, N. was angry and literally came back again and again formore nips. She got pretty damp the first night, and we were bothfrustrated.
Two days later, she started licking me for the first time ever (conceding that she wasn't Top Bun), then tooth-purring.
She also would come up to the spray bottle, nose bump it and then startrolling it around, as if to say "Hey, I can beat this thing." She'svery sassy and bossy and more or less hates being told No. But she's afar happier bunny now than she was when she was trying to make me toethe line.
It took a lot of patience on both sides, and she's still nippy at times- but the nips are pretty gentle; no hard "chompage" like before.
using a spray bottle wasn't an easy choice for me, but I'm glad I didit. Nibbble is not a grudge-holding type; if anything, she stays angryfor about 30 seconds, then wants more affection and petting. If shewere anything other than Ms. Alpha Bun, I'd have hesitated, and stillwould do so. But she needed to learn that her behavior wasunacceptable, and nothing else seemed to get through to her.