Sharing a story like that is completely unacceptable. A teen girl's sexual exploration is a very personal matter. It should be respected as private. Public discussion of such things can make the girl feel embarrassed, ashamed, and can also have a negative impact on her mental health.
Tell the person sharing the story that it is inappropriate and disrespectful. Then, try to protect the privacy of the teen girl in any way possible. For example, if it's in a group setting, change the topic to something more positive and respectful.
No. Such a topic involves inappropriate and private behavior that is not suitable for public discussion, especially in the context of a classroom which should be a place for learning and appropriate behavior.
These stories are not that common in the sense that most teens don't go around sharing such personal experiences. However, in today's more open - minded society, there may be some who are more comfortable talking about sexual exploration in general. But still, when it comes to a teen girl's first time masturbating, it remains a very private and individual experience for most.
Education is key. Teens need to be taught about appropriate behavior in public and private spaces. Schools, parents, and society as a whole should play a role in this education. For example, sex education classes can include lessons on respecting boundaries and appropriate social behavior.
She could try to gather evidence against him. If it's a fantasy world, there might be some magical or technological way to record his blackmail attempts. Then she can use this evidence to expose him and get help.
No, it is completely unethical. Everyone has a right to privacy, and such a story involves a very private and personal moment. Spreading it is a violation of that person's privacy and can cause great harm and embarrassment to her.
It's completely inappropriate. In a civilized society, we should respect the boundaries of others' privacy. A story like this involves a very private and potentially shameful situation for the girl. No one should be made the subject of such a story being spread around, as it goes against basic principles of respect and decency.