i remember looking through this forum and someone asked how does steve vai hit a note behind a fretted note. that got me thinking, by the way i don't know how steve vai does that, or have heard him do that, i barely know his work :(!

well tinkering on the guitar, i noticed if you fret with your right hand, well for me, index finger from right hand (picking hand), put the index finger over a fret, works best with with the 22nd fret for me (22nd being the last fret i have), and you tap behind it with your left hand, you'll hear a chime type of sound. sounds louder with gain, and treble up.
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anywho if you tinker with it, you'll create some pretty cool chime effect sounds, almost like richard wright's piano sounds from the song time (dsotm).

my question is what is the proper name to this technique, if its a technique at all and any tips on it.