Do the parents know about their fear? You could get a parent to hold the dog in a leash sitting nicely (maybe after a big walk or something so he'd be pooped out) and get the kids to just pet him? Or if they have a muzzle or something they could place it on the dog while the kids are assured that he won't bite since he has it on..and get them use to the dog. Tell us how everything goes! and we'll be expecting lots of pics