I have a 7 month old Cavachon. He is really lovely. Very sweet. But he still likes to mouth, which is quite annoying. How do I stop this behaviour. He is not at all aggressive, just very playful and over enthusiastic with all visitors. Nothing I've tried so far has curbed this behaviour and some of my childrens friends perceive it as biting and makes them not like him or want to come round. Help please.