Cool Sister Observation Diary – Secret Masturbation Caught on Camera

Synopsis

I have an older sister. Normally quiet and indifferent, she’s like a cool, detached heroine straight out of an anime—Rikka. (If only she were 2D, I’d be so into this… sigh…)

Then one day something happened. (Was my room always like this??)

I can’t pinpoint exactly where, but something felt off. So I decided to set up a fixed-point camera in my room to observe. (Is something being recorded?)

When I played back the footage, I saw something shocking…!