Your writer has to unfortunately admit that it took him some time before he understood this was a thing in CS:GO. There is a very predictable spray pattern every weapon has in this game, especially the AK-47 and both the M4 rifles have an easy to control path you can follow. It follows the form of the number seven, which you have to counter by moving your mouse the other way.
The easiest way of practicing is to make a game for yourself, with or without bots, where you spray against the wall and see the pattern emerge. With the next magazine you can try to counter that pattern and see how you can group the impacts more closely together. This in turn will make it easier for you to spray down enemies as you are in control, not the weapon.