I hoped that riding the unicycle backwards would feel like ice skating backwards. And in key ways, it does.
Years ago I would take a Coleman lantern out to the frozen lagoons at Tenney Park in Madison late at night after the lights were switched off and other skaters were gone. I couldn't skate backwards very well, and I was on a mission to learn. Skating backwards then felt extremely tentative and a bit scary because I hadn't developed much edge control, had a fear of falling backwards and also because of the unnaturalness of the action. When do humans ever go backwards fast under their own power?
That feeling came back to me when I was working on idling. In order to work both foot positions I was rocking (with support still) around five times with one foot up, then riding backwards three strokes and rocking around five times with the other foot up. I think some other blogs have called that a stretch idle. Riding that backward segment required me to lean back into the unknown and use wheel control to keep balanced and ultimately stop. That sequence of sensations was very familiar. That doesn't mean I did it well, just that it felt familiar, so I have confidence that I'll be able to do it with time and reps.
Can't do backward crossovers on the unicycle, though!