Kanokon/YMMV

Signature Scene: The spanking scene at the end of episode 3, where Chizuru tricks Kouta into spanking her over the desk, is the most (in)famous scene in the series; being a perfect demonstration of the series' fanservicey elements. It has also inspired jokes about being a repressed memory or childhood trauma for those who watched it.
Squick: The recurring scenes of Chizuru's attempts to seduce Kouta, for some, were a bit disturbing or odd as he appeared like a child or atleast significantly young. He is actually just a very young looking teenager, but his appearance and Chizuru being 400 years old still makes it a bit offputting to some people.
What Do You Mean It's for Kids?: This series was very popular among elementary school children in Japan a few years ago. This is despite the series' well known sexual content and numerous NSFW scenes.