It all started when I was a teen boy. Our grandmother came to visit and she had to sleep in my sisters room. So that meant that my sister had to sleep in my room with me. She was 3 years older than I was. It was summer time and very hot out. Of course we had no AC to keep cool. I liked to sleep in my underwear to try to keep cool and she wore just a pair of panties and a T shirt. As I got into bed my sister went to the ba...