While I was waiting in the living room while my girlfriend was getting ready for a date, her sister came home in the morning! I didn't know where to look because she was wearing a daring outfit that almost showed her underwear, and suddenly she started to provoke me by giving me a handjob! I care about my girlfriend, but I can't resist being seduced by such a sexy sister! I took her provocations seriously, which escalated from her giving me a blowjob in secret to her coming to me in the night, and I got addicted to the thrill and sense of immorality! In the end, she found out, but I didn't care and just kept pistoning and cumming inside her!