Be My Slave (2012)

Original title: 私の奴隷になりなさい

Dan Mitsu stars as Kana, a female employee at a publishing company who strikes up a sexual relationship with a younger co-worker. He soon discovers that Kana's fetishes extend to sadomasochistic tendencies, involving a mysterious man only known as "Sensei". This discovery will push his relationship with Kana to a new, dangerous level that he may not be ready for.