Does anyone else here crack the side of their foot? It's really weird, but it's something I've been able to do for a long time… If you draw a line from between the pinky toe and the one next to it, out to the outside of the ankle, that's about where it pops. I pop it by putting my foot down on the edge and then rolling the top towards the floor and applying a lot of pressure, either by standing on it or using my other foot to push down.
It doesn't pop all the time, but it feels great when it does!