When I went to my girlfriend's house, her sister, Hinata, was there instead! She stopped me from leaving and made me sit on the sofa, teasing me with her massive J-cup cleavage—something my girlfriend doesn't have. As my heart raced from her aggressive advances, she whispered, "I'm so jealous of my sister... having such a kind boyfriend," and kissed me! She gave me a vacuum blowjob, saying, "I love your balls," and when she pressed those heavy, gravity-defying breasts against my face, my reason collapsed. After an overwhelming titjob that completely hid my cock, she straddled my rock-hard shaft and inserted it raw. I reached a twitching climax during a jackhammering cowgirl position while she showed off our joined parts. I felt an unprecedented excitement as her breasts bounced wildly with every thrust, and I desperately moved my hips. She demanded a creampie, and I ejaculated a massive amount of cum deep inside her pussy! I've become completely addicted to this immoral sex with my girlfriend's busty, nympho bitch of a sister while my girlfriend is away...