How to stop the pendulum swinging

I have an acquaintance whose gonads – not to be confused with Leibniz's abstract (and hence invulnerable) monads – should be clapped between two breeze blocks; thus demonstrating Newton's third law: “If a force acts upon a body, then an equal and opposite force must act upon another body”, on the surface of it, offers little-to-no comfort to those righteously genitally exposed to brutally administered contraception for inappropriate reproductive activity. Unfortunately, in this case, it isn't a retroactive solution.