Observing Human Behavior: An Experienced Older Sister Teaches Her Younger Brother About Sex!?

Cast

Kasumi Matsumaru

Category

Voyeur

Maker

ムラっch

Released

2025-09-11

A high school boy is seen alone in a room, nervously checking condoms. It seems like he's practicing for his first time with a serious attitude. Suddenly, an older sister from college sneaks in! She quickly tries to hide but soon gets caught. The older sister, concerned about her younger brother's naivety, teaches him how to put on the condom properly. However, she doesn't stop there and begins teaching him how to handle female bodies as well…