Yomibito Shirazu ~Amai Meshibe no Seichoushi~

There's a school where the supernatural is commonplace, and a new style of learning has been implemented. It is called the "Ship" system, where two students learn as a very intimate team. The more trust and devotion you have for one another, the better the rewards. Even so, there is "Ship-Duels" and "Ship-Swapping" and so forth. Each "Ship" has certain attributes attributed to them, and you'll periodically be tested on how well the two of you are doing. There are a few students that you can "Ship" with, and a potential of around 7 women to have sex with. (From Hshare)