My dad remarried with a single mother and suddenly I had a sister. I hadn't even gotten used to living with the four of us yet, but my parents went on honeymoon, so I ended up living alone with my sister-in-law. I have to study for my exams, but I can't help but be curious about my half-Japanese sister-in-law's big ass! I got excited by her big ass sticking out of her denim shorts, and I couldn't resist and came inside her right away! I thought I could just do it, but she refused to have sex with me, so I begged her to give me a blowjob. My sister-in-law's blowjob technique was so good that when I ejaculated in her mouth, she swallowed it right away. I got even more excited when she drank my sperm, and my erection wouldn't go away. During the few days my parents were away, I neglected my exam study and had my sister-in-law suck me off and drink my sperm many times!