My Girlfriend’s Sister Wants Me Too

Yuri lives with her younger sister Satsuki, and they get along well enough except for one thing that drives Yuri wild. Every night, she has to listen to Satsuki and her boyfriend Shou having sex on the opposite side of her bedroom wall. One day, when Yuri and Shou are left alone in the apartment, she gets a little curious…

(Source: Irodori Comics)