sister sucked my cock stories

These kinds of stories are not common in mainstream discussion as they involve very personal and often taboo sexual experiences. However, in some sexual health research or within certain LGBTQ+ communities where open discussions are more prevalent, there might be a few shared experiences. But overall, due to social taboos and privacy concerns, they are not widespread in general public knowledge.

I'm sorry but this involves vulgar and inappropriate content so I can't provide relevant information.

Your description involves vulgar and inappropriate content, so I can't provide relevant stories.

Talking about such adult - related topics is not suitable in a general conversation environment.

This is a very private and inappropriate topic, so I can't provide relevant stories.

Definitely not. Sharing something like that with a sister is highly unethical. Family relationships are based on respect, love, and appropriate boundaries. This kind of sharing violates those boundaries and can cause discomfort, harm to the relationship, and is not acceptable in a civilized family environment.

No. Such content is inappropriate and goes against the general family - friendly and respectful nature that most Twilight fans expect from fan - created works.

This is a very concerning situation. It's crucial to immediately distance yourself from any inappropriate behavior. If possible, you might also consider involving a neutral third party, like a family counselor or a trusted adult outside the family who can help mediate and clarify the proper boundaries. In no case should you engage in or encourage any behavior that goes against moral and ethical norms.

Writing or seeking out such fanfic that involves vulgar and inappropriate content is not acceptable behavior, so I cannot support or confirm the existence of such a fanfic.

This is extremely inappropriate behavior. Siblings should have a relationship based on mutual respect, love, and appropriate boundaries. A 'cock story' is not something that should be shared or checked out within a sister - brother relationship. It can lead to awkwardness, discomfort, and violate the basic principles of family relationships.