A girl is bored and wants something to do. When she complains to her brother, he suggests she play at being a horse. One thing led to another and by the end of the summer she was in full horse tack pulling her brother around in a cart.
When you were a teenager, did you ever had "a thing" for your best friend's mother? How about for your best friend's sister? How about your own mother and sister? Did you think there was something wrong with you? Did you believe those people who said that kind of thing meant you had a sexual addiction, and needed therapy? Or did you decide you were just a normal teenager, surrounded by hot women and evolution was simply making sure that men wanted to do their part in keeping the species going?
Twin Brother and Sister raised to be very close to each other make love at a party and later made love with each other in their apartment. They found that their love making was genuine and they wanted to continue making love with each other after they graduated from college. She told him that she wanted to have his babies.
Older sister seduces her younger brother. They begin making love often and thought that she was protected by an IUD. She missed two periods and began having morning sickness. Her OBGYN told her she was pregnant.