Grip for serving

I play with a forehand/shakehand grip, but I have noticed that when you guys are showing different types of serves, you alter your grip, and then slide back to your normal grip.  I have searched the internet and couldn't find anything on it.  Could you share what the grip is, and how and when to use that grip for serving?  Thanks so much.

Hi TJ,

This is a fairly simple transition.  All you need to do is take the 3 fingers off the handle of your bat and put them in a fist behind the handle.  This allows you to use your wrist more freely for the serve.  Once you have serves just place the fingers back onto the handle like you normally would.