UMD-1003 An unexpected incident during bareback sex!! Accidentally slipping in while practicing sex with my sister!! 12 Kitaoka Karin

Karin is a caring younger sister who lives in the same house as her two older brothers. Both brothers have girlfriends and are close to them, but they each have a unique problem: they don't know what to do about sex. Brother (1) has a girlfriend, but sex with her doesn't go well. He can't seem to penetrate her. Brother (2) has his first girlfriend. He's a virgin and doesn't know how to interact with girls, let alone have sex. Seeing her brothers in such a state, their kind younger sister decides to give them some naughty lessons. However, because they are siblings, they start with just mutual masturbation, but as the sister gets aroused, she inserts her penis. To her surprise, her brothers are actually pretty good at it! They had been doing mutual masturbation for various reasons, but they couldn't hold back any longer and started penetrating each other!