思春期真っ盛りで背伸びしたがるお年頃の妹にオナニーしてるのを見られ慌てて隠したら「私だってそれくらい知ってるもん!私がしてあげよっか?」と…
My younger sister, who is in the midst of puberty and wants to act grown up, saw me masturbating and when I hurriedly hid it, she said, "I know that much too! Shall I do it for you?"