Having sex with a minor is a serious illegal and immoral act. Even if the other party pretends to be an adult, adults should not have sex with them. Once adults discover such improper behavior with minors, they should stop immediately and take the following legal self-protection measures: 1. **Promptly and proactively report the situation to the public security organs: cooperate with the investigation of law enforcement agencies, do not conceal or try to evade responsibility, and truthfully state the course of events and their own behavior. 2. **Actively cooperate with the judicial process: including providing relevant evidence clues, attending court hearings on time, etc., to ensure that the law handles the case fairly. It should be emphasized that the law protects the rights and interests of minors. Having sex with minors is a serious illegal act under any circumstances and will be severely punished by law. At the same time, adults should always maintain awe of the law and moral bottom line and establish correct values.