An acquaintance of mine taught himself to fly helicopters in a Sikorsky S52 that he purchased many, many years ago.
He had a fixed wing licence already and coupled with that experience, taught himself to perform running take-offs and landings. He never felt
safe
slowing down to the point the machine would hover, so hired an instructor to teach him that part. After mastering his hovering, he completed the requisite flight hours, passed his commercial check ride and never looked back, immediately picking up a commercial flying position.
According to another good friend, there is never any doubt in your mind that he taught himself to fly helicopters, should you have the misfortune to fly with him!
