I don't think anything of my little sister's body, but one day I was surprised to see her in a sports bra! I made fun of her, saying, "You're a schoolgirl now, but you still haven't graduated from sports bras!" But when I looked closely, I found her surprisingly erotic and got an erection! My little sister noticed and said, "You're getting hard even though you're saying that," and came closer! She even played with my erect dick, and I couldn't help but shoot a lot! Then, this time, she took my dick in her mouth with the face of a grown woman...