My best friend and I started dating each others sister and we spend most of the time together, at school, weekends, holidays. We went to my granny's house, since my granny died the house is closed that's why like to go there for the weekends. We had planned a night out but the girls didn't feel very good so we went out only the boys. We came home late, drunk and feeling horny. We found them sleeping in the same bed, they said they felt afraid being alone in the house. When we were at the bedroom and seen them sleeping I decided we could try something different that night.