I saw it... My sister's room is always messy. She's been wearing the same ugly tracksuit since middle school. She's addicted to her phone and her eyesight is terrible. To top it off, she's a shut-in NEET. A textbook shut-in girl... Of course, I wasn't interested because she's my sister. But then I saw her having a serious masturbation session! In that instant, my morals, ethics, and sanity went out the window. I became a sex-crazed monster, obsessed with my sister! Even her dry, shut-in pussy woke up! I couldn't help but repeatedly thrust into her until she reached multiple orgasms...