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, 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.
This is rather inappropriate. However, if we consider it in a non - vulgar sense, perhaps in some fictional or symbolic stories, it could be a way to represent an over - exaggerated characteristic for the purpose of satire or to show an extreme in a character's physicality, but this is a very rare and odd concept in proper literature.
Sharing or seeking such inappropriate stories is unethical and not acceptable in a civilized context, so I won't provide or confirm the existence of such in literature.
This could be a very strange or misphrased statement. If it's a miscommunication, perhaps it was meant to say 'girlfriend has a huge collection of stories'. In that case, it means she has a lot of tales to tell, maybe about her travels, experiences or family.
Writing or seeking such fanfiction is inappropriate and goes against the general positive and family - friendly nature of the Naruto franchise. Fanfiction should focus on positive aspects like character development, new storylines within the acceptable moral framework.
Definitely not. Such stories involve private and inappropriate information. Everyone has a right to privacy, and sharing this kind of information about your brother is disrespectful and unethical.