You use flick-on headers when you want to slightly alter the plane of the ball but keep it going in the same direction to find a teammate behind you. Often it's done by the attacker on the near post to find a teammate behind them at the far post. Or, it's done on a long punt or drop kick to put a teammate in behind the defense. The first exercise: a partner tosses the ball, and the player flicks the ball on to the third person and turns around; then the service goes the other direction. The second exercise has the attacker flicking on the ball over the defender's head. The key factors of the flick-on header: you want to jump to meet the ball, you want to keep your eyes open and your mouth shut. Lift the chin; flatten the forehead. The forehead glances on the bottom of the ball. Flick-on headers will help you find a teammate that's behind you when the ball is served to you in the air.