Now, though Eliza was incapable of thus explaining to herself Higgins’s formidable powers of resistance to the charm that prostrated Freddy at the first glance, she was instinctively aware that she could never obtain a complete grip of him, or come between him and his mother (the first necessity of the married woman).
There are no more uses of "prostrate" in the play.
Show samples from other sources
Francis chose to make it his cross to bear in life; he never understood why his Uncle Atticus remained on excellent but remote terms with his father—Francis thought Atticus should Do Something—or why his mother was not prostrate from his father’s eccentric, therefore unforgivable, behavior.
Harper Lee -- Go Set a Watchman
He sat down on the edge of the bed and softly kicked Colin’s prostrate body.