This isn't something I'm worried about, but I am a little curious. When Flower and I have a training session, and she has to repeat a trick several times to get it right, she starts to snap her jaws and bare her teeth. Then, she barks. Is she getting frustrated, and do your dogs do the same thing when they get frustrated- if it is frustration? BTW, she's a seven month old standard poodle, if that helps.