I'm not posting this as any kind of confession, jut a mind-bender that, admittedly, I have no idea how to deal with.

I'm 24 and happily married with no outside needs. We have a fairly large house of four bedrooms so we sometimes have a guest or two for holiday or long weekends. My husband provides for me in every way.

Briefly, the last holiday weekend we were visited by my father-in-law, Dan, his wife and my little sister, Ginny, who, at 16, is normally in a prep school away from home. We are all a close family. On a late Sunday afternoon, I went looking for one of my vacuum cleaners upstairs and heard a "whopping" sound cadence coming from one of the two master bedrooms. Curious, I walked up to the bedroom and peeped through the door that was cracked open.

In the bed, my little sister was atop my stepdad, riding him like a wild cowgirl and his hands were totally wrapped round her bubbly little buns. Her back was toward me and her little body hid his face so they could not see me. Shocked, my initial instinct was to rush off. But I was mesmerized by the fact that my little sister's body was taking in a cock that did not look real, it was so big. I guessed that the hard cock was a good 10 inches and thick around, beer car size. Her vagina was taking it all the way that it could go as she rode Dan. His son, my husband, is seven inches on a good day, and nowhere near as thick.

I felt I had to pull away from the vision lest I be discovered. I went downstairs without the vacuum and could not stop thinking about it for many reasons. Soon, I was sitting in wet panties. Sooner or later I must get Ginny to fill me in on all of it. Now, I'm thinking of how to approach the subject...or even if I'd better let sleeping dogs alone.