Sekirei. One of the non-childish animes. It's a bit on the graphic side, but not quite yuri status. There are approximately 108 participants, aka sekireis, in a game known as "The Sekirei Plan." Minato, a young college-aged boy, is trying to get into a college, but fails. He accidentally meets sekirei no. 88, Musubi. She is unable to attack the two sekireis who are after her, because she has yet to become emerged. She kisses Minato, and then he becomes her Ashikabi, and she emerges. Then the real fun begins...

I rate this one friggin rated R