I was dating this girl in college and I went home with her one weekend. Her folks were out of town, but had invited her younger female cousin to come spend some time with her,not realizing that I was going to be there. The cousin was 17 and not bad at all. I was fucking the college girl when the other girl walked in on us. She stood and watched for a bit, then left. The girl I was fucking went out to bring the girl back and told me I was going to fuck her too, so she wouldn't tell on any one. We both worked on the girl and within 10 minutes, she was ready to go. The college girl guided my dick into her cousin's pussy and it was all good from then on. She was willing to try anything and we all 3 had a great time for the rest of the weekend.