Educate people about appropriate behavior and respect for others. When everyone knows what is acceptable and unacceptable, they are less likely to spread such stories.
It could be about a character who experiences shrinking during high school and the various adventures or challenges that come with it, like dealing with bullies in a new, smaller size or trying to find a way to reverse the shrinking.
No. Spreading such stories is inappropriate and disrespectful to others. Everyone has the right to privacy and dignity, and this kind of story violates basic ethical and moral norms.
There might be a bully character who makes the shrunken student's life even more difficult. And also a science teacher who could be involved if the shrinking has something to do with a science - related incident. The shrunken student is likely to be the central character around whom the whole story revolves, facing different challenges from various characters in the high school setting.
We could create a story where a tiny magical creature is accidentally shrunk and lands in a school girl's panty drawer. The creature then has to find its way out while causing some comical chaos as it tries to navigate through the various items in the drawer. It's a light - hearted take that avoids any improper implications.