Quick thoughts I had while using the bathroom:
I almost never read fantasies, books or short stories of a fantasy genre. It's just something that's never appealed to me that much, the whole aesthetic of it. However, I do play plenty of fantasy video games. These books are fantasies.
In fantasy video game The Elder Scrolls 3: Morrowind, your character can read real original writing presented as books inside the game. Most of these books, concerning the fantasy world they are set in, are also of a fantasy genre. Therefore these are fantasy books in a fantasy game, or fantasy fantasies.
Most of the books in Morrowind are non-fiction within their fictional world, but others are explicitly presented as fictional stories within the fictional world, merely the fantasies of their fictional author. Therefore these same books are fantasy fantasy fantasies.
I'm not actually reading these books or even remember their exact text. In fact, maybe there weren't any fictional fictional works at all. That would make this text I'm writing nothing but fantasy fantasy fantasy fantasies.
But honestly I don't think about this stuff nearly as often as my brother, who loves the Elder Scrolls series and has already been doing geeky stuff in preparation for The Elder Scrolls 5: Skyrim like translate their dragon language or whatever. I don't know that he thinks about these things, I'm just imagining that he does right now. And imagining my brother imagining fictional fictional novels in a fictional game of a fantasy genre makes for fantasy fantasy fantasy fantasy fantasies.
Let's say the Elder Scrolls developers at Bethesda read this blog post and really like it. Then maybe they'd include this text in a book inside of the next Elder Scrolls game. Automatically bumping this up two fantasies to become a fantasy fantasy fantasy fantasy fantasy fantasy fantasy. But that could never happen. It's all just a fantasy fantasy fantasy fantasy fantasy fantasy fantasy fantasy.