[Marneko] Wakuwaku! Rinshou Jisshuu Joshika Suit Sexy Medical Studies! Girlification Suit [GTF]

A boy pulls on a seamless girl-shaped suit and watches a phone app tick the transformation toward completion while his older brother supervises every percentage. Reborn as Yukito, a busty twintailed schoolgirl whose new crotch holds only a 'female approximation' of his old equipment, he gets a very thorough hands-on inspection from his big bro. What starts as a curious experiment between brothers ends with the fresh girl moaning that her belly is full of her brother's cock—her boyhood forgotten somewhere beneath the skin.