How to throw a striaght curve

we all know roy oswalt’s curve starts straight then dives and I figured out why.
most on us hold our curve with our fingers directly across from each other so when you release it the ball has to go over your thumb causing it to rise then drop but if you but your finger under the ball it doesn’t interfere with the release so the ball comes out straight then drops…whewwwwwww… I was typing a mile a minute

Oswalt throws 2 different kinds of curves including a kucklecurve.