My sister, who recently entered college, met a boyfriend! Having been thoroughly educated about contraception, she starts practicing condom use on her younger brother, me. Due to her clumsy attempts, I get a full erection and end up begging her—if you're going to use me for practice, you should give me some service too. What begins with handjob and blowjob soon escalates to full sex! But then the condom slips off, leaving us in a bareback incestuous situation... Even so, since it feels so good, is it okay to keep going with creampie sex? What will you do, big sister?