Here is my take on stick stirring. I feel 9 times out of 10 the person who you think is stick stirring is actually someone who is out of control. You've saddled up on his six, fired a few rounds at him making some nonlethal hits, and have taken him by surprise. Realizing he's in trouble, he attempts to make a hard break turn, or go into a scissors, but in the attempt pulls in a bit to hard on the stick or kicks in too much rudder. Now he's either in a stall, or on the leading edge of one. He attempts to get his plane back under control as quickly as he can without getting shot down. You see his plane gyrating all over the place and have come to the conclusion that he is stirring the stick to avoid you.
In reality you caught him totally by surprise, and his over reaction to your attack has caused him to loose control. Now I am not saying that no one at all doesn't stick stir but the vast majority of the time it's not. Even when my squad does training, I see what looks like stick stirring from a fellow squad mate, but actually it's just a loss of control issue. Granted there are times when you loose control and manage to quickly get back under control. You end up with an advantage on your pursuer, and because of this you would be accused of stick stirring.
AH2 flight model is not as forgiving as AH1 was, and getting into a loss of control problem is much easier to do now, especially if the intended target is a newer person, who hasn't learned to fully control his plane in combat. That is just my 2 cents on stick stirring.