About 1hour later i got a txt from Dawn asking what time i woud be home i said was thinking about comeing now as it was not nice up here she sent one... back telling me dont come home for about another 2 hours as she was busy teaseing John i sent back and said ok when i did get home they were sat in the kitchen talking Dawn had on a full track suit but a big smile on her face i said nothing about an hour later John’s parents came home and he left but not before Dawn told him to call round. Combined with the midrift of her blouse, her stomach, navel, and a good portion of her abdomen were exposed. God, what a lovely tummy she has! And the view from the back was just as enticing. Her skirt came up only to the dimples right above the cheeks of her ass. The graceful curve of her lower back could be easily enjoyed by anyone who cared to look.She was wearing no hosiery with open-toed sand-colored wedgies."You look so wonderful," I managed to gasp out, ogling this vision of beauty and. Err with your cock…?” “Chrissie you want me to fuck your bottom?” She nodded. “If you don’t mind, just gently you know and your semen will work better than any enema – there’s so much of it - and it’ll be more fun and much sexier!” What could I say? My beautiful sexy sister wanted me to penetrate her anus and fill her back passage with my semen. Who was I to argue? Besides, my cock was already standing to attention with the thought of sliding into her tight backside. I took her into the bedroom. ”Alarm bells went off in my head when she said that. I’d already swelled to about half hardness between how sexy she was, and catching a whiff of her perfume. Seeing her incredible ass in that skirt peeking out from below the lab coat didn’t help matters when she gestured for us to follow, even though I wisely only looked for a fraction of a second.We passed through the door she’d entered the lobby through, and it looked like any other doctor’s office. The level of conversion was almost.