Thanks for the advice Clara. I've contacted their trainer again to get a few pointers. I'm leaving one upstairs and the other downstairs while I'm out or unable to watch them. I just tried the self correction thing I mentioned. Kaedyn started looking at me as if to say "What? Did I do something wrong?" Then I allowed him enough space to lunge and self correct him again, he decided to back off so..*crosses fingers* I hope it's just a little phase.