Definitely not appropriate. Family relationships are based on love, respect, and appropriate boundaries. This kind of description involves extremely abnormal and unethical behavior. It is not something that should be part of any story or real - life situation. We should uphold positive family values and ethical standards.
No, it is extremely uncommon and highly abnormal behavior. Such a situation goes against all norms of healthy family relationships and basic moral and ethical values.
No. It is completely inappropriate for a mother to teach her son sex stories. This goes against normal family ethics and boundaries. Such topics are better left to appropriate educational resources like sex education classes in schools which are designed to handle these sensitive matters in an appropriate and age - appropriate manner.
First, if it's just a stupid joke among peers, you can have a conversation with those involved about appropriate language and respect. Tell them it's not okay to use such vulgar terms in relation to your son.
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.
It's completely inappropriate. A mother should be a role model in propriety. Such stories are not only improper in terms of content but also may make the friend's son feel uncomfortable or even exposed to inappropriate information. It's much better to engage in conversations about things like sports achievements, cultural events, or recent interesting news.