My Sister and Her Friend Are Too Sexy – FANZA Doujin

Synopsis

Your mother orders you to tutor your sister after her math grades slip. When your sister refuses to be alone with you, her friend joins in to help with studying.

Your sister’s friend, with her outgoing personality and impressive teaching skills, takes an immediate liking to you and isn’t shy about physical contact. Your sister, meanwhile, grows jealous and competitive.

Before you know it, you’re caught between them both!

Which will you choose—your tsundere little sister in the throes of puberty, or her well-endowed, somewhat gyaru-like best friend?

【Miu】(海羽)

“Why do I have to do this… Having my brother teach me is the worst!”

Your real sister. Tsundere, though not particularly dere. She does care about you, but hits adolescence and gets embarrassed around her older brother, so she acts prickly instead. Bad at math. Has a complex about her best friend’s bust.

【Riko】(莉子)

“Wait, you can see? Oops! Sorry about that… It’s embarrassing, but… if it’s you, Onii-san, that’s okay.”

Your sister’s friend. Large-breasted. Mature-looking and mature in personality. Straightforward about wanting to get intimate with someone she likes—loose morally, but not indiscriminate.