Human pup play teaches everyone involved the value of leadership. The structure of the play, whether between a pup and owner, or within a pack, has the owner and trainer telling pups what to do and how to do it. Your owner and trainer is there to get you doing what you are supposed to be doing, and he fosters and maintains positive relations between everyone in the pack. Without this leadership, human pup play often devolves into just mucking about in some fetish gear.
Sometimes one thing takes precedence over the other. In training it is important for your trainer to get things done right, and in play it is your owner encouraging everyone to share pleasure and have fun. So the direction and guidance of leadership does change according to the circumstances of the scene of course, but the practice of leading does not. Certainly in other forms of bdsm the master can sit on his arse and just have submissives do everything for him. Not so in pup play.
An owner and trainer does his role because he wants to have a positive impact on his pup, to be and have been an important person in his pups life. Doing that well means your owner and trainer has to do several things.
You owner and trainer has to set goals for your training and help you accomplish them. With a pack involved, he actually has to build it - enlisting pups into the pack and building the team as a coalition whilst smoothing ruffled feathers. A good owner and trainer makes his pup feel special, persuading his pup to participate and be better than he is now. And a pup looks up at him and sees someone he wants to follow.
Where a pup is brave and a potential inspiration to others, an owner and trainer is someone that more than a pup can look up to. His leadership helps his community, and his confidence affects his peers so they engage in bdsm more confidently and competently. On a personal level, an owner and trainer leads his pack towards collective success in training and in enjoying the rewards of play.
Your owner can also speak for you pup, and the pack, as he will take the initiative in social situations. That taking charge can range from commanding during urgent situations, to organising the pack so they work together, even to explaining to others what is involved in pup play. As a pup, you look to your owner and trainer to protect you in public areas, and to solve complicated problems and resolve conflicts to keep the pack together. Your owner and trainer doesn't need to be hostile or possessive to do this, instead he can calmly assume his leadership role with the knowledge his pups look to him and support him. That support is given because he deserves that support, his reward for what he has already done in helping you to develop your pup self. Your trainer will have helped you do tasks and practices better, earning your respect and support.
For all of us, leadership is a personal quality we can develop. It requires being aware of our social environment and behaving effectively within it. As a person you may feel shy or insecure, as a pup you practice and develop social skills in pup play, and you can eventually bring them across to everyday human social situations. You can see the value of leadership in pup play and then find yourself becoming a leader in social situations. It is done by emulating the qualities of your owner and trainer, the behaviours they have demonstrated by nurturing your pup self and always being concerned for your well-being and progress. You have seen that leadership is about promoting, directing, and managing social action - guiding other people to do what is appropriate in the scene they are in. Leadership is grounded in a need for dominance, but you have seen how dominance does not have to be destructive for others and instead can nurture and help them learn and grow to be independent and fulfilled. The simple maxim is that in human pup play, a dominants power is used constructively for all involved.
It can and does happen in bdsm that some masters use their power over others for their own self satisfaction. These masters use their social skills and charisma to ensure those they are controlling are submissive, enacting degradation on their pups to ensure control and to reduce and destroy their pups sense of worth and self. A good owner and trainer will actively focus on your welfare pup. Avoid a master who has a self serving or warped view of what you need as a person and as a pup, or simply wishes to dismiss your needs and wishes. Remember a dog loves his master and trusts him absolutely, so we all despise dog owners who abuse and harm their pets for their despicable abuse of that trust.