mom tells son to cum inside her stories

This could be about a mother teaching her son appropriate behavior in the context of storytelling. For example, she might be guiding him not to include inappropriate or vulgar content in the stories he tells.

Mom instructs son not to put any improper elements in the stories she tells.

This kind of story is completely inappropriate and should not be discussed or considered. It goes against moral and legal principles.

Maybe the son came up with some clever schemes that the mom didn't expect and fell for.

No. It is not a proper English expression. The word 'cum' is inappropriate in this context and makes the whole phrase seem very strange and not at all a normal way of communicating in English.

This kind of content violates moral and ethical norms, and it is not suitable for discussion.

This is not an appropriate or ethical situation in the context of a traditional relationship. In a committed marriage, having an extramarital relationship with a 'boyfriend' goes against the vows and values of marriage.

You should firmly refuse. This is not a proper or healthy behavior. You need to respect yourself and your friend's long - term well - being.

One consequence could be that the son might get misinformation. For example, if it's a story about values and the mom makes a mistake, the son could develop a wrong understanding of what's right and wrong.

The most obvious consequence could be the breakdown of the marriage. The husband, if he finds out, is likely to be extremely hurt and angry, leading to separation or divorce.