Hey guys, thanks for all the comments. The pass is self-thought. Basically trials and errors. I'm working on it for couple of months now. I'm a leftie, oh btw my English isn't good so it's hard for me to explain, but I think my right hand does almost all of the work, a relaxed but firm grip, the specific thumb motion, that's it. Just practice, experiment, do all kinds of crazy moves and find what works best for you.
Cheers.