Performed by sisters! - First up is Yuuko, the older sister who has a cool and beautiful image. - She has a bright personality and is easy to talk to, and she is currently a piano teacher. - She grew up in a strict and cramped family environment where both of her parents were teachers, and she had a normal sex life with four people in her hometown, but she moved to Tokyo from Nagano to enter Tokyo music college, and lived alone and had a difficult time with the people around her. Feeling the freedom of not having to worry about her eyes, she had sex with a man she met on a blind date, and now she is a lewd and free-spirited woman. - Please take a look at her sister's lewd behavior as she gets wild and cums without even knowing that her sister is performing. - In the second half, she reveals her lewd nature in CA costume.