As Attitude and Power equals airspeed or altitude/height.....and the Auto-Pilot is maintaining height (thinking of the bottom of the approach)....what is counter-intuitive about having to lower collective (reduce power) to slow down?
If you do not adjust power as the aircraft levels due to the auto-pilot attempting to maintain a height....the aircraft will pitch upwards and slow down.....fail to add some power and you might well get too slow, lose auto-pilot authority and see a downward trend on height.
If the basic laws of flight escape you....perhaps you might just be in the wrong profession.
A few minutes of practice now and then is a simple way to stay in touch with those basic relationships.