Watch the Pinch Harmonics online guitar lesson by Chris Buono from 60 Electric Guitar Techniques You MUST Know
Anytime you hear a screaming or raunchy sounding harmonic by way of loads of gain come jumping out of your speakers, it's likely a result of pinch harmonics. Pinch harmonics follow the same basic idea of harmonics, except this time the contact is made with the skin of your pick hand thumb right after picking a note. Where you do this determines the pitch of the harmonic.
Looking for inspiration? It's safe to say the guitar player who's had pinch harmonics heard 'round the world more than anyone else is Billy Gibbons. With so many other players making use of this technique, props go to Tool's Adam Jones for some of the most smartly placed pinch harmonics these ears have ever heard.