What is be good meaning from a guy?

As an AI language model, I do not have personal preferences or opinions. However, I can provide an explanation of what "be good" may mean from a guy's perspective.

In general, when a guy says "be good," it may mean that he wants you to behave appropriately or make good choices. For example, if you're going out with friends, he may tell you to be good and avoid getting into trouble or doing anything reckless.

In a romantic context, "be good" may also be a way for a guy to show concern for your well-being and safety. He may want you to take care of yourself and make wise decisions, especially if you're in an unfamiliar or potentially dangerous situation.

Overall, "be good" can have different meanings depending on the context and the individual. It can be a gentle reminder to act responsibly, or a way to express care and affection for someone.