The original video shows speed control by what he calls drift and what I call curving side slip. Same thing. Different wording might connect better with different people.
I disagree with the instructor with his lack of counter. I like the upper body always facing down the bump run. I also strongly disagree with the way he holds the pole plant and pivots around it. Make the pole plant, then get off it and counter the other way. I think he's teaching a bad habit. I want to be ready for the next turn before my skis are headed down the fall line. I'm looking one or two bumps ahead. This one looks good to turn on..that one looks better...plant, I'm turned, and looking ahead for the next one. The steeper the hill the more I reach down, way down, the hill ready for that pole plant.
Ways to be doomed on a bump run--
--Lean back toward the hill. Gott'a get the head & shoulders out, way out, down the hill.
--Twist the body around toward the hill. Face the body down the bump run.
--Sit back on the heels. Gott'a stay balanced on the balls of the feet.
My ankles don't flex much in my 130 flex boots that work great for me. By pushing the feet forward to lighten the tips when they need to go up a rise on the snow, or pulling them back, sometimes way back, to get the tips down to the snow works every time.
A friend got a great bump lesson at Whistler where he learned about the Green Line, the Blue Line, and the Black line to ski. He tried to explain it to me. Does not resonate for me. Different people, different learning styles. I can ski his Green Line as slowly and as smoothly as he skis it, but I don't see it as a line. That's just me.