That is a really humiliating position to a fighter: being pinned by a woman who is basically seated on her. And adding insult to injury, giving her backside to the loser.
The initial example (a still image) is a paradigm of arrogance. The second scene (quite sexy), from Japanese pro-wrestling, has also some entertaining views and unusual hip thrusts. And the final scene (sexier yet) has the well known Nancy Novak applying the idea in full nudity for Joan Wise.