We got back from our trip last night.
Middle Son showed some significant new communications methods over the course of the trip. When the situation at the retreat house overwhelmed him, he would bring me his belt (which I use to attach him to his service dog) to tell me that he wanted to leave. Another time he communicated the same desire by taking hold of Willow's leash and bringing her to me.
After I got home from work tonight, he did something new. He brought me over to the counter where I keep my keys, phone, work bag, etc. He pointed to my lap-top bag. I wasn't sure what he wanted. I told him he could pick the bag up if he wanted to. He picked it up and went into the living room.
It occurred to me that during our trip, I had Middle put his backpack on every time we left the house. His backpack wasn't available, so he was using my bag. I asked him if he wanted to go somewhere, and he signed yes.
So we got in the car and went to the library.