I change lenses all the time, on the fly......while driving my car, walking, or dashing about in a hurried fashion. I never really thought about how I was doing it - it's one of those things that just happens - one of those things that your hands and fingers "just do" without your brain having to think about it.
If I am driving thru a wildlife refuge or national park, and see something from the road that is worth stopping for, and the "wrong" lens is on my camera, then, while I slow down and pull over onto the shoulder of the road, I change lenses at the same time, so that by the time I have brought the car to a stop, the correct lens is already on my camera. I do this, literally, hundreds of time every year.
I think that once you change lenses several hundred times, it just becomes second nature, and you will be able to do it within a couple of seconds, even while you are also doing something else. If you have trouble doing it quickly and mindlessly, then I suggest swapping lenses while you are at home.....yes, actually practice it, hundreds upon hundreds of times, in your living room or your den. Then, when it really matters and you are in the midst of a complex shoot, you will be able to do it on the fly, and not miss any opportunities.