You've had a reincarnation and found yourself in a different world. The game allows you to interact with your favorite Waifus in any way you see fit. It's up to you to decide what you want to do. You can get by just talking to your Waife. However, you can also engage in sexually explicit behavior with them. This is a new world, but just because it's different doesn't mean it's a bad place. After all, there's plenty of action if you're into these creatures.