Slider How?

How do you throw a slider?

When I asked the guy who would become my pitching coach for a little over three years—I said to him I just wanted to ask him something about the slider—he seemed to know immediately just what I wanted to know, and he drew me aside and showed me how to throw the pitch. He said, “Throw it like a curve, but roll your wrist, don’t snap it.” He showed me the off-center grip he used—neither two-seam nor four-seam, but in between—and demonstrated the wrist action, which is like pulling down a window shade (or a karate chop) but much easier; you just turn it over a little. Then he handed me the ball and said “Go ahead, try it.” While I was familiarizing myself with the wrist action, working from the full windup, he watched me, and I got the impression he was making some mental notes—like observing that I wasn’t very fast but I could throw hard and was using a slide-step, and that I had a natural sidearm delivery.
I got the hang of it in about ten minutes, and he said “That’s it. You’ve got the idea.” And I did; in a short time it became my strikeout pitch, the one I could count on. I think that the fact that I threw sidearm made it easier; some people who throw overhand or three-quarters might have a more difficult time with it. There may be different ways to throw that pitch, but this was the one I learned. The thing to remember is that you have to throw it, and all other pitches, with the same arm motion and the same arm speed.
And what that pitch did to the batters…

Thanks for the post