Although the story may be odd, it is actually very enjoyable.

The main story is about an Aunt who uses her Nephew to recreate an old story of a man who falls in love (and sexually conquers) 14 Women.
Most of the incest comes in when the Aunt wants to get her Nephew used to a womens body, and allows him to---ehem, you can read that yourself.

It's not hentai, but it is strong ecchi. The story is intresting because the Nephew is so very selfconscious. So, this experience helps the Nephew to grow, as a person.

This might sound strange, but it really is fun and enjoyable. The anime isn't like Aki-Sora, or YnS, in the sense that it is exploring the taboo and boundaries of incest, in this story, incest is just there for....is it the comedic effect? Or just the story? It's not there to be a lesson. I think it's just there to be fun/funny.