Well, this is easiest if you don't go in as fast as you can, more about medium-speed. Go into a normal fingerroll, but as soon as it's on your finger, jerk your finger up to the top of the cord, and then down again and then back up again and repeat. You want to be moving it about 3 times a second. Whenever you move the finger you should feel it hit against the place where the cord joins the chuck.
Now this move is incredibly difficiult with chain, so I'd only try it with cord to start with.