Desert nailed it. Muscle memory.
There is absolutely no way on earth for me to teach you to rapid fire without jerking the trigger. There is no way for me to teach you to quickly draw from a holster or any other skill.
You can be shown, but than practice will make it happen. Learn the trigger reset for your particular weapon. That goes to hell when you switch guns, but the knowledge of how to develop the skill will make it less painful the next time.
"Whats the first aid procedure for consumption of coolant?"