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 with everything—my studies, my private life, and even how I take a bath. As soon as she sees my uncircumcised cock, she says, "You have to wash it properly! Otherwise, girls won't like you!" and tries to peel back the skin to wash it. She's already beautiful, but when she touches me like that, my cock quickly hardens into a full-grown erection! At first, she was surprised to see this, but as she began to move her hands in excitement, it felt so good that I ended up cumming on her! I thought I was in trouble, but my sister, aroused by my grown cock and the cum I released, looked at me with a super erotic face I'd never seen before and said, "Hey... shall we do something more adult?"