I have a much older sister who is incredibly beautiful, but she's also quite overbearing. Even though I'm now a high school student, she still treats me like a child, meddling in everything from my studies and private life to even how I take a bath. The moment 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 for me!! She's already beautiful enough as it is, but being touched like that made my cock harden in an instant into a full-grown erection! At first, my sister was surprised, but as she continued moving her hands with growing excitement, it felt so good that I ended up cumming on her! I thought I was in trouble, but seeing my grown cock and the cum I released made her horny. She looked at me with a super erotic face I'd never seen before and said, "Hey... shall we do something more adult?"