This series cracks me up. I did some searches on it, and apparently it is meant to teach english to japanese otaku. Problem is,
Unfortunately, many of the English examples in the book are bizarre, unnatural, or downright incorrect. Replace: "When I fell down the stairs with my classmate, my body was replaced with her."
So it has become an engrish legend instead.
The attached wrapper on the book says: "Buy now, falling love with Ink-chan, and GET IN to college!!"
http://www.answers.com/topic/moetan

Note: This is not spoilers, it's nothing concerning the storyline in the anime.