Definitely not. In proper English, we don't use such a construction. The misspelling of 'boyfriend' is a basic error, and the 'bull sex story' part is not only ungrammatical but also has a very strange and improper connotation. English expressions are usually more organized and follow certain grammar and semantic rules, which this phrase clearly violates.
This phrase is really puzzling. Maybe it was a wrong typing. If we assume 'boyfreind' should be 'boyfriend', it still doesn't make much sense. 'A bull sex story' is not a common or proper expression. It might be some sort of made - up or very local slang that we are not familiar with. Without further clarification, it's difficult to give a definite meaning.
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, you could start by not making it a big deal in terms of being overly focused on that one aspect. Build the emotional connection first. And when it comes to the physical part, make sure you both are comfortable with exploring at a pace that suits you both. It's all about mutual respect and understanding.
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.
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.