https://www.dlsite.com/maniax/work/=/product_id/RJ01137377.html
https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_322750/

妹のように思っていた無邪気で明るい幼馴染は、昔と変わらないように見えて実は大きく変わっていて…。
沙良は近所に住む2つ年下の女の子で親同士が仲が良いこともあり子供の頃はよく一緒に遊んでいた。
しかしある時、沙良のお父さんが亡くなってしまい遠くに引っ越してしまった。それ以来会うことはなかった。
それから数年、俺が大学生になったある日家に帰るとなぜか沙良が家にいて、しかもしばらく一緒に暮らすことに。
昔と変わらない元気な様子に安心していたが、ある時風呂に入っていると沙良が突然入ってきて…。
「沙良、もう大人だもん…」
秘めた想いとともに身体を晒す沙良。
その言葉通り沙良の体はエロく魅力的に育っていた。

[Synopsis]

My innocent and cheerful childhood friend, whom I thought of as a little sister, may not have changed much from the old days, but in fact she has changed a lot...
Sara is a girl two years younger than me who lives in the neighborhood and our parents were close, so we used to play together often as children.
However, one day, Sara's father passed away and we moved far away. I hadn't seen her since then.
A few years later, when I became a university student and came home one day, I found Sara there for some reason and we decided to live together for a while.
I was relieved to see that she looked just as energetic as before, but one day, while I was taking a bath, Sara suddenly came in...
''Sara, I'm an adult now...''
Sara exposes her body with secret thoughts.
True to her words, Sara's body had grown erotically and attractively...

Base +22, Miosan389 +6, 2468113z +6