I remember seeing a hentai where the guy was watching a porno while the sister was"sleeping" in the bed next to him. He knows she is not asleep so he starts teasing her to see how long it will take for her to stop pretending to be asleep.
Pic is not related (but I think she had the same hair color).
It also skipped to another guy and girl after they were done.
I also think she was kind of a Tsundere
Oh forgot to mention. She wanted him to have sex with her while he thought that she was asleep so she could use that to blackmail him, but because he knew she was awake he used that to cancel her intention out.
Also im not so sure about what happen in the story about the other couple(s?) because I didnt watch it.