Its not necessary for a dog to see another grafting mate ,not at all .if it wants the life you will be digging him sooner or later and you can both learn along the way .i cant stand the hole ending ,short dig some are so used to as it does nothing but you may be goaded into it with your dog tied nearby .Walk the land with him on a lead and try at a few easy places ,hopefully ,that he will ,may mark when hes ready .Pulling on the lead in the mouth of a hole is all i require from a young un to let him off into the darkness .