"All done" is one of the first phrases infants learn, and it ends up being a very good early word to teach to dogs, as it provides a way of marking that something has ended. For this reason, it pairs particularly well with PLAY, allowing you (and them) to mark the start and end of a high importance, and high interest, activity.
If your learner does not have a NO button, it is possible that they will use ALL DONE to register their desire for something to no longer be the case, and may confuse it for NO.
Meanings and uses
Done playing, eating, etc.
Indicate if another dog was being bothersome.
Learner can indicate when they're finished/done with something.
For us to tell our learner something like "food all done" or "play all done", etc.
Indicate the end of a task or activity.
Allow the learner to ask that someone else be finished with a task or activity.
Among our group of successful modelers, the following techniques were used successfully:
Hit the button before stopping the game. Hit the button when there was no more food to eat.
Assigned the ASL movement for "all done" and then signed "food, all done". After doing so, took his bowl or his toy (whatever is "all done" with) and placed out of reach.
I would press "all done" when we had finished playing and then I walked away. Used it when the learner asked for more food to say the learner is all done eating. It was also used at the end of a session of petting the learner.
Used "all done" when walking away from the couch to start task. Even though this did not involve the learner directly, they were nonetheless watching inquisitively.