Go to the girlfriend's house to play the young girl's girlfriend

Today was the first day I went to my girlfriend's house to play. She lived with an older sister but today she was absent because she had to go on a business trip. Talking with her lover, she suddenly returned. It turned out that due to the confusion side of the partner, the business trip was canceled. Do not know because of accidental or her, she brought her beautiful big round butt to her in front of me when my girlfriend went to make tea. That night, her perfect butt image was constantly appearing in my head, making me unable to sleep. If you want to make love, my girlfriend does not give, I'm planning to solve the toilet when I suddenly heard a groan coming somewhere. Following the groan, I saw that Arisu's room was open, looking inside when she discovered that she was masturbating! I officially admire her beautiful big butt! I was engrossed in watching, she also discovered me. But instead of being angry, she pulled me into the room, allowing me to kiss her and have sex with her! Unlike my girlfriend, she gave me love to her whenever I want. And since then we have been stealthily having sex with each other while I still preserve my relationship with my girlfriend ...