Everyone. Please. Write "fuck." "Damn." "Shit." "Motherfucker." Don't fucking censor. Don't write f*** when you mean fuck. Let's not encourage censorship. Let's recognize when we are participating in censorship and self-censorship. You don't have to censor your words on tumblr. You don't have to censor your stories on AO3. Please. Please. Write out the word "fuck."
If you personally don't like the word? Then there's no need to write it. If you are writing a story and you know the character curses and you don't feel comfortable writing it? Write "Character cursed." No reason to disrupt the writing, infantalize the writing, and create an ugly piece of work by writing "Character said, 'F***!'"
We can all handle the word "fuck." Please, please, just write out "fuck." I don't know what you're trying to get out of "f***" but I promise, it's not going to have the effect you want. If you really hate the word "fuck," feel free to be creative and insert another fun word. Anything but "f***."