You can use a clicker however you want, so long as it's effective. I did use a clicker with Charlie when he was beside himself with excitement - this was mainly at the vet's when he was injured, needed surgery, was under exercised and an over excited nightmare. I used it to mark the fraction of a second of 'less mad'. It did work with him. As he calmed down in various environments, I switched to a marker word 'good' because I didn't have to be so precise with the marking of 'a bit less mad', and I was saying 'good' after a couple of seconds of calm, then I could start training a settle which is best done without a clicker. The clicker worked for me, it was powerful for Charlie, more powerful than food alone. With Betsy, who had a completely different life experience from Charlie, I could train settle at home without a clicker, then get that behaviour outside, and just quietly drop food for durations of settle. But this wouldn't have worked in a million years with Charlie, because I would never have got anything to start rewarding. A click is only a release if you have trained it to be a release by the positioning of the treat delivery, and you can switch from it being a release to it being 'stay in position' between different activities so long as you are consistent.
When we went to training classes, our trainer used a "quiet hand" to calm dogs. Having said that, he was into Reiki so you may wish to consider this The advice was to place one hand each side of the dog, just over the shoulders, be calm yourself, don't speak, just do the laying on of hands and wait until the dog calms. I must say it was moderately successful for most dogs who would settle and sit or lay down. (maybe of course he was streaming his Reiki powers through us all into ours dogs) I have an open mind
