A Magnus drop ball works by creating higher air pressure on the top of the ball. The most efficient way is to have the seams orientated so that for each rotation of the ball four seams pass directly over the top of the ball moving towards the catcher. This is called 12/6 spin (as viewed from the catcher's perspective) and can be seen using 90, 0, 6:00 P. M., 0. 3:00 in the Spin Visualization Tool
There are two common ways to produce that spin. One is called the peel drop and it is simply the 4 seam fastball with a emphasis on the finger push as the ball leaves the hand to make the spin go faster. Also the spin should be 12/6 or very close to it.
If the pitcher is using a 3 finger grip the ball will roll off of the index finger tip last which makes it difficult to precisely control the direction of the spin. It is better to use a release the has two fingers touching the ball at release. This can be a grip where the 4 seam stripe is between the 1st and 2nd fingers or the second and third. Alternatively the pitcher can lift her middle finger off the ball just before release and have the ball roll off the 1st and 3rd finger tips at the same time. The amount of lift of the finger tip on the second finger should be very small so as not to tip of the pitch,
The other common way is called the rollover, or turnover, drop. Grip the ball like a 2 seam fast ball and rotate the hand over the top of the ball at release, pushing with the side of the first finger against a seam. It can be helpful to allow the hand to turn up slightly during the 4th quarter as a way to increase the speed of the spin.
Some pitchers will throw the rollover drop so it rotates like a two seam fastball instead of a 4 seam fastball. Since only two seams pass over the top of the ball on each rotation it will have less drop. But the pitch can be combined with some SSW effect to create lateral movement in addition to the drop.
Another option for throwing a drop ball is the SSW drop.
There are many web sites that teach the drop ball and many clinicians will teach it as well. Since each pitcher is different it is a good idea to experiment with new ideas. But don't necessarily start using the last thing you heard. Make sure that any change should increase the spin rate and/or the accuracy of the spin.
