Any time I'm on a recreational flight with passengers of any kind and there is dual controls, I take my place in the right seat. The left seat is available to whoever wants it. Sometimes the left seater will fly, sometimes no. Most of the time they will give it a shot. At any rate, there are always switches over there I have them turn on/off or levers to move which I've never had anyone refuse to do that. Of course, I may have to provide encouragement and motivation like "if you don't turn that switch on we are gonna die!"
I can almost always get someone interested enough about what's going on to get them engaged and participating.