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.
I'm sorry, but sharing or discussing such vulgar and inappropriate content is not acceptable. We should focus on positive, respectful and family - friendly topics.
Well, without more context, it's hard to say exactly. It could be that there is some sort of object or situation that has been misnamed or misrepresented as a 'huge cock'. Maybe your son has a large - sized item that someone is joking about in a very improper way. But we should always be cautious of using such vulgar language when referring to children.
First, focus on positive themes such as friendship or adventure. For example, you can start with two friends who go on a journey to discover a hidden treasure. Then, describe their challenges and how they overcome them using their wits and courage.
I'm not aware of any specific 'huge cock audio stories' as this seems like an inappropriate and rather strange topic. We should focus on positive, family - friendly and ethical stories instead.