Sheltered From the Rain with You - Tsukasa Aoi (2011)

Tsukasa Aoi, a young granddaughter, finds herself in a compromising situation with her grandmother's teacher. The teacher takes advantage of Tsukasa, engaging in intense and explicit sex acts, including creampie and handjob. As the scene unfolds, it becomes clear that the teacher is the one fucking Tsukasa, and the central kink revolves around the taboo nature of their relationship and the explicit acts they perform.