Since that unforgettable day 5 years ago, Nanami and I have become brother and sister due to our parents' remarriage... We've always been close, but when I saw Nanami's breasts getting bigger and bigger as she grew, I couldn't help but make sense. I feel like I'm going to lose it. So when my girlfriend's parents were on a trip overseas, she begged me to let her masturbate while I sucked her breasts while she was on my lap, and she reluctantly obliged.