I think Cody was just stressed, insecure, anxious or even bored in that situation and dogs do various things to offload stress or boredom when they feel it. My Tibbe yawns when he is lightly stressed or bored. Most "professional" training sessions are 30 minutes long or more - way too long for my liking as dogs rarely can maintain much interest in training for that long. In nature, dogs don't line up for training sessions so we must keep the training very short, frequent and fun and engaging for them. It may just be body shaking is how he chose, or chooses in the future, to handle light stress or boredom.
His reaction could be something in the nature of the training techniques or tone of voice, body attitude, etc., of the trainers he interacts with cause him some degree of tension or boredom. Are they/you making the training fun, interesting and upbeat for him?
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |