Yes, you can rub the gel on his teeth but right away get him to engage in some sort of chewing activity. Either a treat or food. Even better if you can apply the gel to his favorite treat or food that he chews. The key is that either during or after the gel goes into his mouth, that he's chewing on something. That chewing activity creates friction which activates the enzyme cascade in the gel. We're also working on putting our enzymatic gel into treats that you can take daily, but that's still in development.