Lust Doll Plus by Indivi version 5.1

Lust Doll Plus is set in a post-apocalyptic semi-modern/future world, where you start alone and confused in a dangerous place, with literally nothing (not even clothes on your back), and go on to carve out a piece of the world for yourself. There'll be a main storyline to follow, but the emphasis is on it being an open world game where you just screw around and have fun.