Straight from the horses mouth. (Satriani)
Between the end of you fretboard and the bridge their is a bunch of natural harmonics if you pick around.
Find a good spot that you like.
Flip your left hand over the top to touch the G and B strings, pick it so you have your harmonics, then dive bomb the whammy with your right hand.
You can catch them when the whammy is already bombed down too, and then let it up but it's a lot harder.
Steve Vai trick:
Pick two notes that you like on one string, trill as fast as you can while shaking the sh*t out of the whammy.
Have fun
