How To: Throw a spiked curveball

In this video you'll learn how to throw a 'spiked curveball'. With this throwing technique you get the ability to make the ball go either down, sideways, or any angle in between.
This technique is all about the how you hold the ball. To perform the spiked curveball you should place your middle finger over the seam and curl your thumb around the ball. With a pretty tight grip, keeping pressure on the middle finger, you place the tip of your index finger on the seam. It is important to have cut your finger nail quite short and neat. Otherwise your nail may stick to the ball and break off both your nail as the ball's effect.
The next step to perform this technique is the position of your wrist. The angle of your wrist determines the drop angle of the ball. I.e. if your wrist is vertical the ball will go down and if you hold your wrist in an angle, the ball will go from top-left to bottom-right.
For the throw itself it is important that you curve your thumb over the ball, to give the ball it's rotating speed and therefore it's effect. Now go and try it out, but remember the technique: grip, wrist angle, and thumb action.