This sounds simple enough, but it may take a few tries. When you hit a purple note with this powerup switched on, a giant pinball will run up in front of you hitting notes along the way, and then make its way down towards you. You'll need to be on the same path where the pinball will fall off to keep it bouncing back along the highway. The longer it remains in play, the faster it gets. Counting the time while you catch it is the only way you can know if you're close to succeeding with this goal.
This will only unlock after the pinball has fallen off the highway providing 20 seconds have passed, so a single track song will not work.