You might want to look into the overused "double tap" and "triple tap" terminology vs actual controlled, deliberate fast shots with a sight picture for each shot.
Now you've done it. You have awakened the monster that is Orange Gunsite Alum. I call him GodCooper.
Controlled pair=sight picture with each shot.
Hammer=multiple trigger depressions with a single sight picture.
GodCooper now returns to his slumber in the sea.
Ummm, ok, but why? Speed will come with time.