i think flap technics is a way for describing how one gets familiar with the way the way to hold the pick and how to get the right amount of "snap" on the string to get a tone tone i guess. the string from your wrist and crap, and also coordination with the left hand. like if you watch a tuner and snap the strings weird (don't break them lol), it can go sharp and stuff, especially on a floyd rose. people do it but it messes up your playing and stuff, when it should feel really natural on a nice guitar. who knows though.
i have seen the void! look out! beware! watch out!