Step 1: Draw flipflops on your feet with a sharpie.
This is as simple as it sounds. I did it in the back of a pickup truck bouncing down the road on the way to a certain establishement.. at night. So it can't be all that hard. Just draw freeform. Consider tattooing for long-term barefootedness, although this might be best done in a tattoo parlor rather than a moving vehicle.