We had a morning BAT session with Lea and her Doberman, Iroc. Chimera had either never met Iroc or had met her when he was a wee puppy; can't remember which it is. We worked in a residential neighborhood which Cai had never been to before, although we did arrive early and walk around for 30 minutes before the session started.
At first I asked Lea to slowly walk around with Iroc as if they were out for a walk. Chimera stiffened and stared the first time he saw them. The decoys stopped, facing us, and we waited. Cai let out one frustration bark but then turned toward me and we jogged away. I also rewarded him with freeze-dried salmon, a particular high-value treat, and one he'll eat in most situations. On the next rep he again stiffened and stared, but no more barking. After a few more reps he stopped becoming so stiff and only delayed looking back at me if he was air-scenting to get more information about Iroc.
We progressed to having Lea hide and then walk out with Iroc in front of our path. That barely changed Cai's reaction. Then we did passes, which made him strain toward her, but in a friendly, wanting-to-greet way. We moved to a different block and did more surprise appearances, which made Cai stiffen the first time, but he responded quickly to "let's go!" At the end we even had Lea and Iroc jog right toward us, and I had to use a little bit of leash pressure to get Cai to move out of the way the first couple of times, but then he started moving out of the way with me.
It looks like Cai now recognizes that when we're doing repeated approaches, he can relax -- he's safe, and he won't get to interact with the dog, but he'll get engagement and treats from me. We have another session scheduled for Saturday, and I'll start with sudden appearances of the decoy heading toward us, since that's what gives us the most trouble when we're out for a regular walk.
I was very proud of how well he did!