My life changed the day I walked in on my sister and her friend Sara having sex. I thought they were outside and I snuck into Laura's room to steal a pair of her panties I could sniff as I jacked off. I stood mesmerized as I looked at two naked twenty year olds, suddenly Sara screamed as she saw me. I turned beet red and fled to my room, of course, I felt guilty as I had just been caught trying to commit a perverted act. Laura came into my room and I begged her not to be mad at me, she said she wasn't mad but she was worried I would tell mom what she and Sara were doing. I promised her I would never tell and I guess she believed me.
A couple of days later she came up with her plan, and after telling me about it, I agreed without a moment's hesitation. She asked me to pretend to be Sara's boyfriend, that way Sara could spend more time at our house without our mother asking too many questions. This was like a dream come true for me, as a kid of eighteen you can believe how cool it was for my friends to think I was dating a twenty year old. The best part for Laura was our mom kept insisting that she be included in our activities as kind of a chaperone. We three were together almost every night, and even if I wasn't the one having sex, just watching those two get it on was almost as good.
Laura convinced me to talk mom into letting us use the cabin for a weekend and of course, my mom agreed as long as I took my big sister to make sure Sara and me didn't get into trouble. There seemed to be no one at the lake and it was as if we had it all to ourselves. Once on the shore in our bathing suits Sara came up to me, as she peeled off the top to her suit she said,
"Laura and I plan to get hot and heavy; I hope we don't embarrass you too much."
"It's OK Sara I understand, I just hope you don't mind me watching, it's so hot to see you two together."
