When I was around fifteen I found some letters my mother and stepfather had written to each other. He was in the services and away a lot. They'd had two kids after she'd divorced my father and it was obvious to me from a young age that she really liked sex. The first of these letters described an incident that took place on a major train station after she'd seen him off at the end of his leave. Being a friendly person she'd struck up a conversation with a man who was waiting for a train.