My stepsister is a quiet, introverted girl whose thoughts are impossible to read. But she has this erotic aura, so I've been checking her out with dirty eyes every day. Then one day, she casually invites me to sex: "Do you want to fuck me that badly? I don't really mind. Just wear a condom. I'll be looking at my phone, so if you want to put it in, just go ahead." If she'll let me in, I'll accept any condition! So, the long-awaited insertion... she really is just watching her phone... and her reaction is weak... actually, there's no reaction at all! But when I secretly take off the condom and fuck her raw... suddenly, my unresponsive stepsister starts moaning and arching her back, cumming like crazy! That incredible gap gets me even more excited, and my hips start moving violently! My stepsister keeps cumming over and over. She acts cool, but inside, she's a super slutty girl.