Uh...uhm...I guess I am," I stammered to respond. "This is a doubly special night," said Matthew and I stiffened at the sensation of his finger slipp...ng into the recess of my buttocks, pressing against my anus and caressing it and sent a rush of conflicting thoughts crashing into my mind. I had my eyes closed for most of this time and I heard the bed creak and then the warm wet feeling of my cock being sucked. I timidly opened my eyes and saw the head of my mother bobbing very slowly. It was. Note to self: frozen logs are cold and shouldn't be sat on by naked butts.Robbie's hand encircled my cock. Her hand was cold, and the feeling was painful and wonderful at the same time. Second note to self: think about restricting outdoor sex to summer months. Maybe fall and spring.On the lake, Tami was circling, gathering speed. I saw her push high in the air and spin twice before landing. A double lutz. Tami faltered, but I ignored her.Robbie was breathing on the head of my cock, and her hot. " I replied.Martin and Tina took their bags upstairs while I headed for the kitchen to make the coffee. As I waited for the coffee to percolate I wondered what the kids and I could do for the next two weeks that they would be visiting me; I had the same problem every year, what to do. Mind you I had always enjoyed the annual two-week visit of my big sister's kids, especially after my own marriage had broken up; they had cheered me up no end. Martin had now turned nineteen, his sister was. Then she sucked our cocks, first deepthroating one then sucking two at the same time.She would rub the tips together and tell us to kiss.We would have done anything and anyone if it meant we could keep fucking her.The whole time she was sucking our three cocks she would give instructions about how to deepthroat,and remember to lick the balls and always stroke it and keep it wet.I did not understand why she was teaching us how to suck cock.But now I get why she did. We continued to fuck her the.