Kidnapped by the Mistress

You and your sister were kidnapped by a strange cute girl with sadistic tendencies - Mary. She grew up in a family where kidnapping is a normal thing, but it's her first time kidnapping people and she'll learn a lot about herself.
Mary wants you and your sister to become her pets and you are not able to disagree or stop her, but you can choose from different answer options that either affect her decision at the moment or allow you to accumulate slave/resist/masculinity/love points that will affect your future.