By having strong moral values. We should be aware of what is right and wrong and refrain from creating or sharing any content that violates basic ethical and family norms.
This is an extremely inappropriate and unethical scenario. In a fictional context, it should be condemned as it goes against basic moral and family values. If such a situation were in a book, it should not be glorified but rather used as an example of wrong behavior.
Sharing such a story is highly inappropriate as it involves private and inappropriate details about a family member. Family members' privacy should be respected, and this kind of content is not suitable for public discussion.
Well, if not in a vulgar sense, 'huge cock' could potentially be a misnomer or a very strange way of referring to something large. Maybe it's a big rooster on the family farm that the stepmom has some sort of story related to. But this is a very odd and uncommonly used way to phrase it if not being inappropriate.