Definitely not. The idea of this fanfiction contains elements that are not suitable for general audiences and violates the standards of decency. Fanfiction should generally strive to be more positive and in line with broader social values.
I'm not entirely sure as I haven't read this specific fanfiction. It could potentially be a very strange and perhaps inappropriate take on the character Harry. It might be a work of fan - created fiction that involves some sort of extreme or unusual situation for the character, but without reading it, it's hard to say exactly.
Definitely. When you follow the steps to delete a Facebook story, such as clicking on the appropriate menu option on the app or web version, it gets removed permanently. There's no hidden archive or anything like that where the story still exists after deletion. Facebook respects your decision to remove the content and it's gone for good.
Yes, sort of. By not posting a story, you are in a way 'hiding' it permanently. If you have a story already posted and you want it to be permanently hidden from everyone, the closest you can get is to delete the story. Once deleted, it won't be visible to anyone.
I'm not aware of any specific "huge cock in tiny mouth stories" in mainstream literature. Most literature focuses on more positive, moral, and diverse themes.
Educate oneself about appropriate communication. Learn about the values of respect and decency. Also, if you encounter someone bringing up such inappropriate topics, firmly but politely let them know that it is not acceptable behavior.
Well, it's not always a straightforward yes or no. Sometimes stories are saved for a long time, like in well-maintained databases or archives. But if there's a system crash or if they're not backed up properly, they could be lost.