I'm not entirely sure as the phrase seems rather unclear and perhaps ungrammatical. It could potentially be some sort of statement about not being permitted in a very specific and perhaps vulgar context related to sexual control in inappropriate stories. However, it's not a common or proper phrase.
No. These are private and sexual - related stories, and public discussion of such topics is inappropriate as it violates privacy and may make people uncomfortable.
Suppose 'cock' refers to a faucet. There might be a story of an old - fashioned house with leaky faucets. A plumber was called in and he told the family all about the history of faucet control. He then showed them how to properly maintain the faucets to avoid future leaks. He shared some of his own experiences of dealing with difficult faucet situations in other houses, which was both educational and entertaining for the family.
I'm not sure specifically what 'cock control stories' are supposed to mean in a non - inappropriate context. If it's about controlling roosters, for example, there could be stories of farmers using special techniques to train roosters not to be overly aggressive. Maybe they use positive reinforcement like giving treats when the rooster behaves well.
Well, 'cum control' is a rather unusual and potentially inappropriate term. Fanfic usually involves fans creating their own stories based on a particular franchise or set of characters. But when combined with 'cum control', it's not something that is commonly found in mainstream or acceptable fanfic topics. It could be part of some very specific, perhaps adult - oriented or fetish - based fan - created content that is not appropriate for a general audience.
Sharing 'cock cum stories' with your sister is extremely inappropriate. Family is a place of love, care and positive interaction. Such vulgar content has no place in family communication. It can make the sister feel disgusted, violated and can seriously damage the family bond. Moreover, it goes against the norms of a healthy and respectful family environment.