
Hi,
I think rather than putting him on the lead when he does this (which could make lead trainingharder!!) I would put the puppy in a playpen when the children come round. Puppies do tend to treat children as they would other puppies, because children are much more exciting than adults. They are nearer the puppy in size, so are less scary, and they have exciting high-pitched voices and darting movements, all of which a puppy finds irresistible!
If the puppy is in a playpen he can bounce around in excitement, but not get too close, so will slowly learn to stay calmer when the children are around.
Hope this helps.
:)