The story from Meatboy on August 26 really hit home for me because my sister and I are exremely close as well. We confided everything to each other while growing up. When she was 16 and I 14 we both decided that we didn't want to appear naive about the opposite sex. We both agreed to show ourselves to each other and learn.
Our folks played cards one night a month so we knew we would be alone. We showered and went to her bedroom where we dropped our robes and lay together. There I let her play with me getting me hard. I had her stroke me until I shot my load. She spread her legs for me and I put my face as close as I could. I played with her clit and labia and finally brought her to orgasm. I enjoyed her aroma so much and over the months I learned how to eat her to orgasm.
We both told each other what we liked and didn't like and eventually couldn't wait to be alone. We became experts at satisfying each other. Some of the best days of our lives.