The best way to teach a pup appropriate play is to let him or her play with a balanced and patient dog that will tolerate but ignore inappropriate play and respond positively to appropriate play so the pup learns whats acceptable and what isn’t.
Here Sampson stands still and avoids Scout’s inappropriate face nipping and demanding barking then when he stops Sampson initiates polite play. He also play bows to show him to stay down to play that mounting or trying to play over top of another dog isn’t accepted. Great job Scout and Sampson!!!