
Hi Guest,
hopefully a Gundog expert will be along shortly to advise (although it may help if you register so you can provide specific info, such as which breed of Gundog).
I ain't got no gundogs, but personally so long as your boy is OK outdoors with kids I'd not try and force the issue at home as I take it from your post that it's a rare event ? If he feels pressured by a child's approach, then biscuits toys treats etc won't work - he'll be too upset :(
If it's not practical to simply avoid an occasionally visiting child having contact with him, work with the child first ;) Get the child to completely ignore the dog, give him his space, don't make cooing noises or invite him to interact. If the child shows no interest in the dog and you also don't attempt to make an issue of the situation, you may well find that your dog eventually comes over for a sniff at the child (probably from behind) and again, just ask the child not to react. Patience with stress issues is usually the most important thing.
It's difficult to give more specific advice without exact info but hopes this helps a bit :)
Regards, Teri