[Amuai Okashi Seisakusho (Yuukey)] Doppelgänger ni Kanojo mo Jinsei mo Ubawarete Bakunyuu JK ni Sareta Boku [GTF]

Aoi's life gets stolen twice—first when a doppelganger takes his identity, then when the same shapeshifter turns him into a busty schoolgirl with a chest that draws every hand in reach. Now sharing a classroom with his former girlfriend Mio, Aoi discovers that being on the receiving end of Mio's affections means experiencing sex from an entirely new angle, complete with eager breast worship and climaxes that leave him seeing hearts. Flashbacks of football games, gym-class ambitions, and a proposal to Mio that will never come underscore every moan with the ache of a life rewritten.