This effect was coined by great
guitarists like
Joe Satriani and
Steve Vai.
Note: Before you try this technique be sure to oil your joints and charge your battery, because if you can do this well you aren't human.
Pick one of your heavier strings, and slide your pick up the string towards the bridge. At the same time, dive your whammy bar down, keeping approximately the same pitch in the process.
The sound this technique produces can only be described as; what something would sound like if you should it down a lizard's throat....