I'm assuming that your hand is large enough to form a complete circle.
You grip the ball with the thumb and index finger of your hand to form a circle on one side of the ball, and your other three fingers rest on top of the ball. The trick is not to grip the ball too tightly---otherwise it will indeed squirt out of your hand! (I remember when I was working on that pitch my hand wasn't quite large enough, so my pitching coach suggested an alternate grip, just forming a half-circle like a backwards "c", which worked for me.) And you throw the pitch the same way you do a fast ball.
Now, I was a natural sidearmer, so I never had any problems with it. It may be that you're getting too much on top of the pitch, which is why you keep missing the strike zone and throwing over your poor catcher's head. Try dropping your arm angle a bit, more like 3/4, and see if that will work---remember, if you can get the ball down in the strike zone you won't throw it wild. And quite possibly you'll get your other pitches down into the strike zone. Try this for a while and let me know how it comes out. 8) :baseballpitcher: