Sister with sadistic hobbies forces her lover to be a slave to her

She has a sweet appearance, a small body, and always smiling eyes. But as soon as he walked into the bedroom, he seemed to turn into a different person – powerful, bold and attractive enough to make him succumb.
His wrists were lightly tied with a silk scarf, and his eyes glanced down with a sly smile. "Today, you have to be good, can you hear it clearly?" – the child's voice was gentle but decisive. He lay still on the bed, without a piece of cloth, trembling with anticipation.
She sat on top of him, her round buttocks gliding across her chest and then sliding down to the place where she was the strongest. Her small hands gently patted his thighs, provocatively: "Don't move unless you are ordered."