Kodi: G rated is the best, but you MUST rate it correctly.

Depends on what it's referring to. Again, be sure to rate it properly. I'm guessing the subject of the joke will likely be the determining factor in that regard.

@Draco what would be a good rating?

That joke is often (censored) related :/ I'd say no, just to be safe, unless you give proper rating for the fan-fiction and give a warning in your description. Maybe PM a fanfic mod to confirm.

If it's a joke that doesn't refere to anything bad then...yes.