"Just keep your ass like that, Nina." Kafka said as he slipped his hands back into her underwear again and slowly pushed his hands in between her cheeks from the start without playing with her ass too much. "Don't move around too much."
Nina was rather disappointed that he didn't grope her ass at all, because, for some reason, when he did, it made her feel like a tool that was only used for sexual pleasure.
The way he grabbed onto her cheeks without any hesitation whatsoever made her feel like she had no opinion in the matter, and she had to quietly endure the slight pain of his fingers digging into her flesh to prove to him that she was the good girl he thought she was.
When she thought of this, she quickly realised that he was swiftly gaining dominance over her mind and body, and he was about to make her completely obedient to him in a matter of time.