I have a beautiful older sister who is much older than me. She's quite overprotective and still treats me like a child even though I'm now in high school. She interferes in everything—my studies, my private life, and even how I take a bath. As soon as she sees my uncircumcised cock, she says, "You must wash it properly! Otherwise, girls won't like you!" and tries to peel back the skin to wash it!! She's already beautiful, and when she touches me like that, my cock quickly hardens into a full-grown erection! At first, my sister was surprised to see this, but as she began to move her hands with excitement, the pleasure was so intense that I cummed right on her! I thought I was in trouble, but my sister, aroused by my grown cock and the cum I released, made an incredibly erotic face I'd never seen before and whispered, "Hey... shall we do something more adult?"