ボクには年の離れたとても美人の姉がいるんですが、かなり世話焼きで高○生になったボクの事を今でも子供扱いし、勉強やプライベートな事には勿論、挙句の果てには風呂の入り方にも口出ししてくるんです。ボクの包茎チ○ポを見るやいなや「ちゃんと洗わなきゃダメだよ！女の子にモテナイよ！」と皮をむいて洗おうとするんです！！ただでさえ美人なのに、そんな風に触られたらボクのチ○ポもみるみるうちに硬くなって大人の勃起チ○ポに！それを見た姉は最初びっくりしてましたが、やがて興奮しながら手を動かしていると、ボクはあまりの良さに姉に発射してしまいました！これはやばいと思いきや、ボクの成長したチ○ポと出された精子に発情した姉は「ねえ…もっとオトナな事しよっか」と普段見たことない超エロい顔をしてきたんです！！

I have a very beautiful older sister who is much older than me, but she's quite overprotective and still treats me like a ***** even though I'm a high school student. She gives me advice on my studies and private life, and even on how I take a bath. As soon as she saw my uncircumcised penis, she said, "You have to wash it properly! Otherwise, girls won't like you!" and tried to pull back the foreskin and wash it! She's already beautiful, but when she touches me like that, my penis quickly hardens into a fully erect adult penis! My sister was surprised at first, but then she got excited and started moving her hand, and I came inside her because it felt so good! I thought this was bad, but my sister, aroused by my grown-up penis and the semen I released, made a super erotic face that I'd never seen before and said, "Hey… let's do something more adult!"