Yes, making him wait until after the other dog has eaten in a good thing.
I would talk to your trainer, and also Google "Nothing In Life is Free" training for dogs. Figure out his motivation, and limit any playtime with other dogs right now - as soon as he shows sign of getting overexcited, call him back to you, have him run through his tricks, etc., to distract and calm him.
When I say figure his motivation - is he food focussed, or toy focused/ What, besides positive attention and praise, is his favorite reward?
Bookmarks