I'm not sure if it's a real story as I've never heard of it before. It could be fictional, as it seems like a rather outlandish and inappropriate concept.
If you are uncomfortable with the story, it's okay to let her know gently. Say something like 'I'm not really comfortable with this kind of story. Can we talk about something else?' This way, you are being honest about your feelings while also maintaining respect for her.
No, it is not appropriate at all. Such topics are very private and often fall into the realm of vulgar and inappropriate content that should not be shared publicly.
No. This kind of topic involves unethical and inappropriate content such as non - consensual and immoral behavior, so it is not suitable for discussion.