Dogs should wag their tail if their owner holds food near them.

If a dog's owner goes within 6 blocks of their dog with any dog with any food item, the dog would wag it's tail. The tail would wag more vigorously if the food item gave more health (check the wiki link below to see how which items give more health.) This is just a basic idea, so comment any possible changes below.

https://minecraft.fandom.com/wiki/Wolf