The Sissy Girlfriend Experiment

A regular guy living with his sister meets an older woman one night, and she becomes his girlfriend. That's the start of it, not the end.

From there the story leans on three people: the sister, the girlfriend, and a close friend whose gender you pick at the start, since that friend is the only one the protagonist actually trusts. Each of them ends up pulling him further along a path of transformation he didn't sign up for, one push at a time.

The game runs as a text-based sim with stats to track, mainly body, flexibility, and mind, which shift depending on the choices and encounters you go through. A clinic run by a doctor gives you room to manage that progress directly, letting you trade experience to shed skills you'd rather not keep, or just talk things over and get a read on where you stand. It's less about set routes and more about watching the numbers, and the person, change.