The story centers on Botan and Shinobu, two childhood friends who enroll in St. Azumaria Girls' Academy. Their encounter with an "angel" named Un-chan lead to strange things happening in their lives. The manga openly describes itself as covering yuri, hentai, omorashi, and other elements of fetishism not usually seen in shōnen or shōjo manga.
Via Anime News Network
I'll post a summer guide 2013 for the list of trailers soon.