So what do pages 3 and 4 mean? Is this book just a story the real Patchouli found? In that case, Is the same true for the other Patchy books by this author? Are there some hypnosis shenanigans going on and she doesn't remember doing this?
@Zakuzelo The first kanji on page 3 read "Several weeks ago..." and on page 4, it says that the thin book she found had depictions of breeding in the human world (aka sex) and she wanted to know more about it. At the first panel on page 5, it says she went to a Doujinshi event in the human world (hence the fat otaku with the bags of merch on page 6.)
So basically the doujin from there depicts how she became the slut we see on page 2.