He simply grabbed a sharpening steel and demonstrated how to run a knife blade along the wand, which he did without flicking his wrist. “Like a conductor,” he said. “You have to keep the angle constant.”
That angle needs to be about 20 or 30 degrees in relation to the steel.
It's not a sharpening steel, it's a honing steel. It doesn't sharpen knives, it aligns the sharp end from \\ or // to /|\ (you're looking at the blade from the heel with the tip pointing away from you). Also, 20-30 degrees is very wrong, Japanese-style blades are usually at about 15 degrees, others around 22.