I am helping a friend of mine work with her German Shepherd doing some casual agility in her backyard. I taught her dog to follow a target but when I remove it, he barks. I think it's because he wants to keep playing (but I don't at that moment). I am very committed to clicker training and am not willing to use any aversives (which is fine because even the gentlest leash corrections upset him even more). Does anyone have any experience with excitable barking and any ideas about how to stop it? So far I suggested turning around / ignoring him and giving him an "all done" signal so he knows he doesn't have the opportunity to earn treats anymore. If anyone has any more ideas, I would appreciate advice so much!