For two years now, after my mom remarried, I have had to put up with my stepsister Trina. She has a pretty face but is way to fat for her age. She is three years younger than me and is a brat. I don't know how long she has been doing it but after my parents leave for work she sneaks in my room knowing I sleep naked all the time. This past March was the first time I surely knew she was doing this. I don't remember feeling it before then but she pulled the sheet off my body. Its warm here most of the time so it didn't wake me right away. I sort of rolled over on my back when I finally realized she was standing there looking at me. At first I thought I was just dreaming or something and the next thing I knew she walked out of my room. My mom and stepdad own a lunch truck business and are gone most mornings by 5am. When I looked at my clock that morning it was only 7. When I did get up I asked her if she was in my room but she denied it. A few mornings later I got up to use the bathroom. My mom and stepdad were just leaving for work at the time and I was only back in bed for about 10 minutes when I heard my door open and could see the light from the hall. I had my sheet pull up around my waiste but had my back to the door and didn't see Trina come in. I was going to sit up and confront her but decided to see if she would do it again. I just layed with my eyes closed then felt the sheet being pulled down very slowly. When it was down at the back of my knees I was going to yell at her. I was laying on my side with one leg bent up and knew she could probably see my scrotum and anus. All the sudden I started to get a hard on and just keep laying there. I could sense her moving around the bed but I didn't say a word to her. I couldn't believe how much it aroused me and she must have stayed in my room for almost 15 minutes looking at me. I finally heard my door shut and was suprized at myself for being so turned on by what just happened. I couldn't go back to sleep after that and instead masturbated. After that morning I began setting my alarm and and sometimes would have the sheet already off of me when she came in. She didn't come in every morning but usually did a few times a week. She mostly came in near 7 am when it was light outside but if she came in when it was still dark she always had the hall light on. I now sleep different ways when I think she is coming in and I always get an erection when she does. The first month or so I would lay on my stomach and didn't want her to see my hard on. I figured it was her doing this and started turning over letting her see it. Her cousin Kim lives a few blocks away and most of the time walks to school with Trina. In the end of April one morning I realized Kim was also in my room looking at me. This just made me more aroused and when I got an erection I started laying on my back all the time. I never maturbated in front of them but would really like to one of these days. I do touch myself once in awhile and always masturbate after they leave. Almost every week I ask her if she was in my room that morning and just the way her face gets red, I can tell she is lying when she says no. For the last month and so far this month her cousin Kim comes in with her at least one time each week and somtimes two or three times. I don't know why I get so aroused when Trina comes in because I have no sexual interest in her. I see her in her night clothes often but have never seen her naked and really don't care to. I would like to see Kim naked but doubt if that will ever happen. I'm not sure if it excites them or if they are just curious and like to see my body and especially my penis and testicals. I even lay on my stomach sometimes with my one leg bent up far and expose my anus to them. It seems like the minute Trina walks in and especialy if Kim is with her I get a hard on right away. My mom knows I sleep naked but she never comes in my room without knocking or asking if I am decent. Trina even comes in on weekends sometimes but mostly when my mom and stepdad are shopping or outside somewhere. I do want to let them see me masturbate but if I do they will know I am awake. I don't want her or Kim to know that I am letting them see me naked so I only masturbate after their gone. The only other girl that has seen me naked is my girlfriend and I have never exposed myself before this. I shouldn't do it but it gets me excited everytime Trina or both of them are looking at me. I cover myself sometimes with the sheet up to my waiste and get hard as soon as she starts pulling it down. Most of the times when I do this I am totally erect before the sheet is all the way off me. I hope some day they have the nerve to touch me but so far they only look at me. As much as my stepdad spoils her I know he would be furious if he knew what she was doing. I like telling her I thought somebody was in my room because she blushes every time I say someting. She just looks at me sometimes and says, why would I be in your room. I never say much more about it and can tell she is embarrased herself at what she is doing. I'll never tell her how much I like them seeing me naked and will continue letting her think she is the sneaky one.