Snap shooting - according to Mssrs Green, LaClair, Hill and Bear - all pretty much the same story and they have it. It's a foreign concept to archers who strive for a mechanical, step by step form and execution. We all start that way to learn. Once you have the form basics down, try putting it all together in an atletic move, like a golf swing or hitting a baseball, and you'll get the idea. That's how most of us "snap-shooters" discovered it. We hit a wall on consistency and groups shooting "static". Then, relaxed and shot a fluid rythm, and bingo, we were shocked by our first 1" group of arrows snuggling together in the same spot. Did I do that? How'd I do that? And, you start learning how to relax and repeat it.
Fluid, dynamic, rythm of execution with correct form (no form elements are left out), all in one smooth motion (generally, more or less, and sometimes we hold)is the good "snap-shooting". As Terry once pointed out - snap shooters tend to aim then draw and execute, and others tend to draw, aim and execute. Keep pulling!