For many women, her on top is the easiest position for them to orgasm during intercourse. So in Devotional Sex a Knight must learn very good self-control in this position so that his Princess is able to reach orgasm without him ejaculating first.
One good way to help him learn control is to set a rule that the Knight is never allowed to ejaculate in this position.
This rule makes this position extra powerful. Not only does her on top have the Princess controlling the action, but it also represents that she will orgasm but he will not.
What fun!
