Wow!!! Love it, thumbs up and kudos!
Like Luke said above, it's just like a thumb push cut. Lots of accuracy and control of force/direction. I never thought you could apply that to fire steels like whittling, it's just pure genius!
On a side note, like erik mentioned, your 'normal' technique needs mod. I would suggest from personal experience that you:
1) place the magnesium rod on the ground surface directly next to at an angle so as to slightly hover on top of the tinder. This will cause your sparks to land directly on the tinder, greatly improving chances of a light. Also, it will help keep things still, and with a firm, steady grip, you won't be bumping your tinder around and showering sparks everywhere.
2) like mentioned above, use slow, higher pressure strikes rather than fast, stiff ones. This will produce more sparks showering for a longer time as you slide the striker down (with a firm deal of pressure being applied downward) on the magnesium rod.