This is a pitch that I have been throwing all you do hold a 2 seam with the index on the left same and middle finger a little toward the middle inside of the seam. You try to put alot of the pressure on the index finger and little on the middle. Then you throw it.
It breaks down and in to rightes it is a reverse slider. It is a pitch that Dice-K, Livan Hernandez, and Greg Maddux throw. It moves alot.

just the proper way to throw a 2-seam fastball.