I ended up staying the night at the house where my girlfriend and her sister live. I was imagining a naughty night on our first night together when her sister seduced me! I was wrapped in her big boobs, which my small girlfriend doesn't have... I love my girlfriend, but I can't resist being seduced by such an older sister! And unlike my girlfriend, who only lets me have sex with a condom, her sister is OK with raw sex! And she's OK with cumming inside! Even though my girlfriend is right next to me, the raw sensation feels so good that I can't stop thrusting!