Sweet moaning voices can be heard from the next room… Even though I thought I shouldn't look… when I peeked in, my little sister was masturbating with all her might!? My little sister, who had grown into a woman's body before I knew it… Gradually reaching climax while awkwardly touching her pussy. My brother felt a sense of eroticism for his too defenseless little sister's masturbation… Unable to resist, he sneaks into the room where she is masturbating.