Sora Aoi is Tsumugi (2004)
Directed by: Hidekazu Takahara
Stars: Sora Aoi, Satoshi Kobayashi, Takashi Naha
Language: Japanese | Subtitles: English (hard)
Country: Japan | Ar: 16:9 | Dvdrip
Also known as: Seifuku bisyojo sensei atashi wo daite
Description: Tsumugi, a girl with a crush on her teacher, discovers that the teacher is having an affair with another teacher. Complications ensue after Tsumugi manages to attract her teacher, but then begins falling for a fellow student.