Hi Gang, After years of playing I've been able to do a pinch harmonic thing as I play. I'm not an expert and did a quick search of what others have posted and there where quite a few so maybe this is redundant but I wanted to pass along some things that I've noticed about how to play them and don't have time to look at alllll of the other posts. Check out the vid to understand what I'm on about. So after all of that, the main things that I've found to producing the sound is hit the strings with the pick at a 45 degree angle and allowing the string to graze the thumb, and have an aggressive string attack. You have to really hit the string so when it bounces off the thumb it still vibrates. Then it's best in the middle of the neck, it's harder at the more extreme ends of the neck. You have to really dig in so there is a lot of energy in the string. To get the string to hit your finger it takes some practice but I've had best luck with just a little bit of the pick sticking out of my fingers. Not like you are strumming chords but really choked up on the pick, and hit it hard. You want to make it squeek. Best of luck, Just my 2 Cents Carry on . . . . .