THIS IS WONDERFUL that Zero is already picking up on his new cue!! YESsss!!! marvelous, wow, that IS a smart cookie indeed! yay!! I'm so excited that you have already figured out a root cause of Zero's tendency to boil over at slight trigger, is the lack of exercise and attention and stimulation and all that stuff. YAY!!! keep us posted, this is very good!!! I think you will solve this problem, i really do!