This story is completely true and it happened between my sister and I. This is my first story that I am submitting on here. So here it goes.
My sister and I have always been close growing up. Our parents we always working and they worked hard to have us grow up well off. We had a nice house, nice cars, and we got almost anything we wanted. The only thing was that our parents were never home. My sister and I were only 3 years apart so we were always doing things together. We knew everything about each other and would always talk to each other about problems we had whither it was about boyfriends or girlfriends or whatever. We were always comfortable around each other and would always walk around the house in our underwear or whatever we wanted. As we were getting older I noticed that she was growing up into a beautiful woman. By the time she was 18 she was about 5'9", 125 lbs, slim body, 38DD tits and a nice ass to go with it. Growing up with her though and see her grow up I was used to it and didn't really think anything of it until one summer when it all changed.
It all started when I was 21 and my sister just turned 18. My parents decided it would be nice to go on a family cruise to the Caribbean. My parents planned the whole thing and we went all out for this trip. It was one of the largest cruise ships in the world and had everything on it. We were so excited to go on it and it is all we talked about for months. My parents booked one room together and another one for my sister and I. They told us that they weren't going to bother us at all for the whole trip and that we can do whatever we wanted as long as we didn't get in any trouble.