Another good exercise is to place your front tire on the top of a curb, and leave the rear tire in the street....
I must be reading it wrong, because I imagine my bike to be perpendicular to the curb with the front end on the curb and the back end on the road. I know from experience in a car that this is never a good place to be
Maybe the bike is supposed to be almost parallel to the curb with the front tire up and as I "go" the rear tire is rubbing along the curb pushing the bike forward (great for removing chicken strips, huh?)