DS (8) is quite nervous around our puppy. He is fine playing with him until the pup gets a bit chewy (as they do) and then he panics, flinging himself on to the sofa like a canon ball and shouting 'No!' at the dog. The dog then thinks this is great fun and chases him. I've told him repeatedly not to panic if the pup nips him, and instead to say 'No' firmly and to stop the game by walking away and being very dull etc. But he's still nervy. Tonight he bent down to look under the sofa for one of the pups toys and of course the pup leapt on his head. DS wasn't hurt, but was frightened and cried. I really wnat them to be friends, so has anyone got any advice on how to get DS to be less nervous? They are never alone, btw, and DS does seem to want to play with the pup. I think it's the bouncy unpredictability that is alarming him.
If you're worried about your pet's health, please speak to a vet or qualified professional.
The doghouse
OK, well firstly puppy teeth do hurt and your DS's reaction is understandable - BUT he's now turned it into a great game!
Google 'yelp and shun puppy bite inhibition' and teach your DS that method. It does really work and obviously everyone in the family must do like wise. Consistency is the key.
Also can you make sure that you tire the pup out a bit before DS plays with him? It might build his confidence if he has a calmer puppy to play with. Also get a nice long chew toy so DS can use that to play with him, i.e. puppy grapples with the chew toy and not DS.
Finally tell DS to wear slippers around the pup so his feet don't get nipped as that REALLY hurts. 
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