女体化のえっちなお姉さん プールのおねえさん編

Ryuuta has a friend who he looks up to. He’s older, taller, athletic, muscular and assertive. One day at the pool, however, his friend spontaneously changes gender. Now she’s older, taller, well-endowed, soft and assertive. After recovering from the shock of what happened in the pool’s shower stall, things between them start going in a weird direction... (Source: Fakku!)