My son is 9.5 months old and loves our two dogs. We have an almost two year old pit, named Milli, and a baby pit, named Steff. Milli usually runs when she sees my son coming. He squeals and grabs her neck fat and her ears. So I don't blame her for trying to avoid him. He does the same to Steff but Steff doesn't seem too bothered by it yet. I tell my son "No!" or "Stop!" when he pulls on them but he doesn't understand he's hurting them. How do I teach him to play nice?