https://www.ammolite-game.com/amml_027/index.html
http://www.getchu.com/soft.phtml?id=1139820&gc=gc
https://vndb.org/v31608

Dude's dad remarriage the two sisters mother so they are his step-sisters.

But their hair color are similar enough to be real siblings.

Production team just too lazy to give the dude different hair color. lol
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wtf p.53, p.54 younger sister eyes changed color... is that double end dildo or she grown dick cause of that eye color?

Base +8

P.76 - Two people f*ck in public, and the rest of the crowd just starts nutting right there and then. I truly love hentai world logic!

Base +9