https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_214788/

Text: 6-328
No Text: 329-623
Omake：624-627

Looks like another younger sister want to steal older sister life to feel better,

Dude date older sis Kana (short hair) some years already, they didn't talk about marriage but do planning their live together.
So dude man up goes to girlfriend house. They never date at her house cause she lives with her younger sister Runa.

Runa smiled but didn't talk much made the dude wonder if she was annoyed by his presence

Dude went in Kana room, his girlfriend, but Runa, the younger sister was naked on bed then she asked "Me or older sis, who's winning?" "Please hold me to find out,"

Dude have sex with younger sis.

Dude keep dating older sis, went to her house more, fucks younger sis every time he can, fill her up.

Then younger sis pregnant. Dude keep date older sis.

p.320-322 dude reason as man animal instinct is to leave seed, nothing wrong if he move on to other female if he already impregnate one.

lol

as this author is no stranger to female cheating in other work, it would be fun if the older sis is cheating already.

Base +8, FudgeSickle +7, VAC +6, fathervice +21, lkoofu +10, observer1980 +21

@H0R0
It's kinda odd Yoriko tries to start a short discourse revolving around interpersonal relationships between a man and woman. She should probably read up on the 1960s - 70s sexual revolution that normalized everything we know about "sex" today before writing off cheating as men's desire to father multiple children and women's desire to one up one another. Those feminists simply made infidelity much easier and stripped away all of the negative consequences by introducing pills, contraceptions, abortion clinics, etc.

Base +7, kaura117 -7, igurust -6, VAC -6