Note: This story was dynamically reformatted for online reading convenience. From that moment on for the next three weeks everywhere I went I could hear or see my naked children having very enjoyable enthusiastic sex. The girls I observed loved to ride the boys like cowgirls, and I noticed Colin in particular loved to shoot his load all over his little sister's bellies and then smear it in until it glistened. Debbie I noticed had a very prominent clit like a little half inch penis and she was always rubbing it in fact all the children were in a state of arousal most of the day. Watching television was accompanied by slapping of hot bodies together and gasping and panting, and I took to masturbating watching them and gave myself some wonderful orgasms. During one particularly hot few days I had been out shopping the children had been in the garden "playing" when the postman a man in his early 60's let himself in the side gate as he had a parcel to sign for and he was greeted by Colin screwing Sandy from the rear doggy-style. Colin recounted the story to me later. "I was fucking Sandy doggy-style and tugging on her small nipples, mum and was just getting to the short strokes when I looked up and saw the Postie, looking at us stunned mouth open hand down his trousers. He smiled at me and motioned for me to continue. Just then the excitement made my balls boil over and I filled Sandy's cunt, and she fell forward onto the grass my cock popping out dripping spunk. She turned and smiled only to see the old postie wanking in his trousers. She was so full of lust she crawled over to the old man who was now frozen like a rabbit in the headlights. Hand down trousers glazed smile. "Hello postie," The naked Sandy said as she went over to him my spunk dribbling down her legs. "Watcha doin'?" she asked in her little girl way although it was obvious. The postman stood frozen until Sandy took him by his other hand across to the recliner on the patio took his bag off him and sat him down. He stared at her nakedness drinking in her smooth body unbelieving it all. I stood to one side gently wanking my spent dick. Debbie and Brian were inside fucking somewhere else. The naked little preteen put her hand on the postie's bulging pants and he withdrew his hand from his pants. "Nice bulge," Sandy commented. "Is it for me?" "If you want dear," the postie grunted as she rubbed the front of his trousers. "Where's your mother dear?" he asked.