Part of it is because he is intact and some of it may depend on his age - hormones raging.
Supervise playtimes of course. Tell Mick, "that is enough" and do the "annnnnt" if and when he starts in on Ponzo. Enough is enough and manners are manners. Rank is going to depend on the two dogs personalities and temperaments. Top dog will be whichever one it is, human interference or trying to make one be over the other when it isn't in their natural being will cause problems potentially. Just be sure they both know you (the humans) are the absolute top dogs.
Debbie