I think we more or less have the party line on pillion dropping a foot or leg; but there doesn't seem to be too much data on other aspects of the vaunted active pillion and their special secrets to making it seem like the rider is a "great rider"???
My wife has been my only passenger for the past 11 years. She rapidly developed due her interest in wanting to be a good passenger and our exchange of riding information, plus she obtained her endorsement when we met. She doesn't fall asleep or space out. She enjoys the ride as much as I do and that is what she is out to do. If she doesn't feel up to it, or uninterested in the particular ride, she doesn't come along.
She keeps her feet up and butt centered, while paying attention to the road, traffic, conditions, and checking our six. We have an intercom which allows us to share information and more importantly for me to feed her what I'm about to do. She responds to this information as we have previously trained, understanding we may come to a point in responding to traffic that each is on their own.
The basic principle is to keep on the bike, stay together. If we go down I want it to be a low side. In that event, stay with the bike and stay with me until ground contact, get the low side foot out from under the bike and push away from the bike with the high side foot. Try to slide and avoid tumbling.
She consistently provides me feedback with traffic, animals and obstructions. I know she is paying attention because she often ask questions along the way to keep better in tune with my intentions. We aren't perfect and ascribe to improve as we learn. At speed, she keeps her feet, legs and butt planted and will lean her upper body to match my body in turns that I will shift my upper body. She tries to keep just enough space between us so she can see ahead into the turn. There are other little things she does to assure she is ready in the event I need to make a rapid maneuver, lacking the time to advise her.
I think the best we can do for ourselves, as the rider, and for our passenger is to keep the discussion open and ongoing to inform them of what is necessary at parking lot speed, through traffic and at highway speeds to have a safe ride. My wife isn't 'just along for the ride', rather she is an equal in the ride. She is my co-pilot and we are a team. We discuss the route, the traffic, the time, the weather, the gear we take, the people we ride with, the destination and options, along with alternatives. She feels as much a part of the ride as I do, because she is.
It's both about the ride and the destination for us. Mostly about the ride, and the good part about the destination is, once we get there, it ends that ride and marks the beginning of the next ride. Good for me, the wife likes to speed. Not silly stupid speed, more like what we may term a spirited ride. She also has a lot of faith in my ability, which is a lot more than I would have if I were the passenger!!