My Fair Link: Yousei Byakuya Monogatari

One day the protagonist finds a fairy falling unconscious in the forest. He takes her home. The fairy tells her story: she fell in love with a human and now wishes to gain a human form with magic. The protagonist wishes to help and supply magical powers by providing sexual magic. This way their unusual cohabitation begins.

My Fair Link: Yousei Byakuya Monogatari screenshots