Teach him about empathy. Let him understand how others feel and how important it is to consider the feelings of a potential partner. You can use examples from books or movies (appropriate ones, of course) that illustrate healthy relationships based on mutual understanding, trust, and shared values.
It is completely unethical. Forcing any form of inappropriate or sexual behavior, even in the context of a story, violates basic principles of respect, consent, and human dignity. No one should be made to engage in any such demeaning act in any situation, real or fictional.
Such a story is not something that should be discussed as it is likely to be immoral and against social norms. It's important to focus on positive and appropriate content.
There is no information indicating that 'Cock Suck on Vacation' is a real story. It might be just a random and inappropriate phrase someone made up. We should focus on positive and respectful stories and topics.