It's very likely a very specific phrase created for a particular situation, perhaps by a small group of people or for a specific piece of writing. It doesn't have the widespread usage that common phrases do. For example, phrases like 'once upon a time' are known across many cultures and languages, but this isn't like that.
If 'cock' is being used in a different sense, like as a slang for something else, it would change the meaning entirely. But generally, if we take it literally, it might be a humorous or interesting anecdote about an irresistible encounter with a rooster. For example, a story where a person is constantly drawn to watch a particularly magnificent rooster in a coop.
It could be that the cock stories have elements like unexpected plot twists or very engaging characters that make them hard to resist. Maybe the way they're told is just really compelling.
A mom and son might resist the social norms of a particular society. For example, in a society where the elderly are sent to care homes as soon as they reach a certain age, the mom is getting old but the son resists this norm. He takes care of her at home, and they both resist the pressure from neighbors who think it's inappropriate. They are happy living together and prove that family values can be different from the mainstream.
Since I don't know the exact 'son in law cock story', it could potentially be a story that involves the relationship between a son - in - law and some sort of situation related to a rooster. Maybe in a rural setting where a son - in - law has an encounter or experience with a cock, like in a farming or village story.
I haven't come across it as a well - known story. It could be something very specific to a small group of people, like a family's own tale that they tell among themselves, or perhaps it's from a very niche area or community where not many outside are aware of it.
I'm not sure specifically as this seems like a rather strange and uncommonly known title. It could potentially be about the wives in Westchester and something related to a son, but without more context it's difficult to say.