When Lisa isn't happy with her slaves, she knows just what she needs to do. She grabs her female slave by the hair and forces her over to the ottoman. She shrank her slave down to the size of a doll and laid her on the ottoman. As soon as she was still, she was happy to sit on the little doll. She put her hot pussy on the dolls face after smothering her with her ass. This will teach her to obey.
When Erina decides she wants to hurt her slave, she only has to sit on her. Erina loves being a giantess for that reason. It's very easy for her to pick her slave up and sit on her. She knows that her slave lives in fear of her big round ass and that is what she wants. When she sits on her slave, she knows she is cutting off air from her but she doesn't care.