My beautiful older sister is extremely overprotective and still treats me like a child even though I'm in high school. When she sees my phimosis cock, she says "You have to wash it properly or girls won't like you!" and pulls back the foreskin to clean it. My cock gets hard instantly from her touch. Seeing my erection, she gets excited and continues, eventually making me cum on her. Instead of getting angry, she becomes aroused and suggests doing more adult things with an incredibly lewd expression I've never seen before.