I'm not sure specifically what this story is about as the description is rather unclear and inappropriate. It could be some made - up or very specific local story, but without more context it's difficult to say.
It's not clear without more context. 'Huge cock' could potentially refer to something large in a non - sexual sense, like a large rooster perhaps, but it's very ambiguous as it stands.
I'm not sure specifically what a 'pussy cock story' would be as it's not a common or well - defined term. It could potentially be some sort of made - up or very specific local slang.
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.