I have also had some similar occurrences in my dreams. In my dreams my control usually comes at the moment of intense fear or lack of control. At this point I can sometimes take complete control of the dream almost to the point where I usually wake up. For example one of my most recent dreams where I assumed control was when I was back home from college in my old room in the 3rd floor of my house with my brothers sleeping. For some reason I was blasted through the window by some force and began falling. It was one of the most realistic feelings I have ever had in a dream. I could swear that my stomach dropped almost like that feeling like you are free falling without any control of where you will end up. Anyway, at this point I seemed to force myself to stop falling and hovered my way back into the window at which point I woke up.
I have no idea why this happens but sometimes it seems like I can control almost anything in my dreams even the physical. Unfortunately this does not occur every time I dream but when I do it is such a rush. The most awkward thing is most of the time when I assume control, unlike the others; I don't realize it is a dream. These dreams are always so realistic that I wake up and have to tell my self that it was a dream.
I just find it really intriguing that the human unconscious can do something like that. I am looking forward to hearing more about your experiences with dream control.