Today is the first day I went to my girlfriend's house to visit. She lives with an older sister but she is absent today because she has to go on a business trip. While chatting with my lover, she suddenly returned. It turned out that due to a mistake on the partner's side, the business trip was canceled. I don't know if it was intentional or not, but she put her beautiful big round butt in front of me when my girlfriend went to make tea. That night, the image of her perfect butt kept appearing in my mind, making it impossible for me to sleep. If I wanted to have sex, my girlfriend wouldn't let me. I was about to go to the bathroom to deal with it when suddenly I heard a moan coming from somewhere. Following the moaning, I saw Arisu's room was open. Looking inside, I discovered she was masturbating! I can officially admire her beautiful big butt! While she was engrossed in watching, she also discovered me. But instead of getting angry, she pulled me into the room, allowing me to kiss her and make love to her! Unlike my girlfriend, she lets me have sex with her anytime I want. And from then on we continued to secretly make love to each other while I still maintained my relationship with my girlfriend...