A-Channel
Tooru and Run have been best friends for ever, therefore when Tooru finds that she's was able to enter exactly the same high school since Run, she runs to tell her... just to find Run in a compromising position with another girl, Yuko. Needless to state, making matters somewhat awkward in the school, with Tooru fending off people that may be thinking about Run while Yuko Nagi, and their girlfriend, have to deal using Run's personal penchant for play.
(Source: Sentai Filmworks)