This is a true story that happened between my stepsister Mary and I. My name is Bobby, and I was 15 and she was 13 when all of this happened. I had just had to move in with my dad at the end of the school year to a small town about an hour away from where I had been living with my mom because she was going to be working on the other side of the country for the summer. I was pretty pissed off with the whole situation because I wasn’t going to be able to see any of my friends all summer, I didn’t know anybody in the new town, and I had only met my stepmom once before. My dad and I were never close either, so I was pretty miserable and feeling sorry for myself about everything.

I knew that I had a stepsister named Mary, but that was all I knew. I had never talked to her, or met her, and I was determined to keep it that way as much as I could for the summer. Boy, was I wrong!

When I got to their house I rang the doorbell and Mary answered the door wearing a bikini covered by a small t-shirt. Right away I noticed that she had the most beautiful blue eyes I had ever seen! She also had medium length dark brown hair, a cute little upturned nose complete with freckles, and I couldn’t help but notice that she was really cute. She only came up to my shoulders, had a skinny body (which I was checking out behind my sunglasses), and two little bumps on her chest, just the bare beginnings of what would later grow into pert B cups, perfect for her small frame. All in all, my little step sister was a cutie!

I introduced myself, and she invited me in, saying that it was going to be just the two of us for a few hours until the old folks got home from work. She offered to help me in with my stuff, and bent down to pick up one of the smaller duffle bags that I had brought, but I guess it was heavier than it looked, because she ended up dropping it and then falling over on top of it, giving me a chance to check out her little ass. One side of her bikini bottoms had slipped over towards the middle, riding up into her crack, and giving me a fair shot of the cutest little butt I had ever seen!

Now please don’t get me wrong, I’m not a pervert or anything, I was just a healthy American teenaged boy. I had never in my wildest dreams imagined that I would be checking out someone from my own family, even though she was in fact not related by blood, but I just couldn’t help it!

So there I was trying not to stare, and I couldn’t help but laugh a bit at her predicament. She got up, angry at me for laughing, blushing like crazy, and stomped off, calling out that my room was at the end of the hallway, and for me to carry my damn stuff myself. I got my things into my room, feeling depressed again about the way things were going. I knew that I had already gotten off on the wrong foot, and so I went and found the kitchen and grabbed a couple of cokes out of the fridge.

I went and found her room (not too hard in a small 3 bedroom house), and knocked on her door, thinking that I would try to make peace with her. She said (still angry) that I could come in, and I handed her the coke and apologized. I didn’t know it then, but I guess she had been teased a lot at school because she was skinny, awkward, clumsy, shy, and not developing into a woman as fast as some of the other girls at school. We started talking and discovered that we actually had a lot in common. I was at the time skinny, not good at sports, and didn’t really have a lot of friends either, preferring to spend my time reading in my room. This had developed as a defensive thing because I didn’t have to hear my parents arguing when I was in my room reading, and since I had begun doing idiotic things to try and get some attention from my parents, it seemed like I was always grounded and couldn’t go outside and play with the few friends that I had.

The more we talked, the less depressed I got, telling myself that it might not be such a bad summer after all. My dad and her mom got home from work, and I could tell that they were tired and not real happy about me being there, but they tried to cover it. After dinner I said that I was tired, and went into my room to watch some TV because it was just getting to be too hard to be social with people that I didn’t really know. I was lying on my bed when Mary knocked on my door and walked right in, plopping on the bed next to me. She was still wearing the same t-shirt, with no apparent shorts on underneath, and that got me thinking again about the brief glance I had seen earlier. I tried not to get too excited, but she was lying next to me on her stomach, facing the TV, and every time she moved, her shirt inched up little by little, until I could see that she was wearing some little girl type white cotton panties that were molded perfectly up into her crotch. She had her feet up in the air, bent at the knees, and was swinging them open and shut, exposing a little bit more each time. I don’t think that she was doing it intentionally, she just wasn’t thinking about it. I was glad that she was there, but I could no longer focus on the movie we were watching, and ended up watching her instead, fantasizing about what was under those panties.

I’ve told you that I didn’t have a lot of friends, but that was even more true when it came to girls. Of course there were a couple that I had asked out, and even gone out with a couple of times, but that was as far as it went. I had never had a real girlfriend, and I had never had any sort of experience that would have counted as even getting to first base. In short, I was a complete and utter virgin, and I was so shy that I had no idea how to even get things going in the right direction if you know what I mean. I couldn’t believe that I was actually seeing a girl half naked for the first time, right here on my bed, and it had to be my stepsister. Of all the rotten luck!!!

Well, anyways, the movie ended, and Mary got up to go. In doing so, she got up on her hands and knees to crawl over me so that she could get up off the bed, and I got to see her bent over for a brief moment and my brain went wild, thinking all sorts of crazy things. My dick had been hard during the whole movie, but the sight of her panty covered ass made it spring to life again just as she was sliding across my lap. I was horrified that she might notice as she slid across me, but it seemed like she didn’t. She said good night and gave me a little kiss on the cheek, saying that she was glad that I was going to be there for the summer and that we were going to have a lot of fun together. She had a funny look on her face when she said that, but I still thought that she hadn’t noticed my hardon, and I just thought she was saying it to be polite. She headed out, going through the bathroom that was between our bedrooms, and I heard her door close. I raced in there, making sure that her door was closed, and sat down on the toilet for the most needed jack-off I had ever had, thinking the whole time about her cute little ass that had just been right there on my bed.

The next day our parents had to go off for work again, and so it was just going to be the two of us all day. She came in to my room wearing the same bikini from the day before, and this time there was no shirt. I noticed that her tits weren’t quite as small as I had thought the day before, but they were still little more than a couple of pointed mounds. She asked me if I wanted to go hang out with her at the pool in the back yard, so of course I said yes, my brain working overtime thinking about her and her hot little body. I know this sounds sad, but I had seen more girl flesh in the few hours that I had been here than I had in my whole life! I followed her out to the pool, my eyes watching her butt the whole time. When we got to the sliding glass door going outside, she turned around to ask me to go back and get a couple of towels, and busted me checking her out! I started to apologize, but she just grinned and said that it was okay, she didn’t mind. She said that it was the first time she had ever caught anybody looking at her body, and that she took it as a compliment. My brain was going a million miles a minute as I went back to get the towels, and when I came outside, she was lying on a chair on her stomach, and she had taken her top off. I got an immediate woody again, and sat down quickly, still eyeing her perfect butt. She asked me if I would mind rubbing suntan lotion on her, and of course I said that I would. I got some on my hands, and started to put it on her shoulders, but it was cold and she sort of shrieked. I laughed and said sorry, and began to rub it in. She began to relax, and I was working my way down her back, across her shoulders, down her arms, wondering how far I could dare to take this. I didn’t want to do anything to spoil things, but at the same time, I was just going crazy thinking about my beautiful younger stepsister Mary! I finished rubbing her back, letting my hands wander down to just above her bikini bottoms, and started to get up. She opened her eyes and asked me to rub her legs too. This was getting to be too much for me, because I knew that here might be a good opportunity to finally have some fun if I didn’t go and do something stupid.

I started rubbing her feet with the lotion, working my way slowly up her legs, the whole time staring at her ass. By the time I got to just above her knees, I could feel my hands starting to shake. I rubbed the lotion onto the backs of her thighs, letting my fingers go a little bit between her legs, but I couldn’t get too far because her legs weren’t open. As I was rubbing, she slowly opened her legs, allowing me to rub farther up, and I noticed that she was beginning to breathe heavily. I began to get more daring, and let my hands wander up towards her butt, massaging more, and she was actually pushing back just a little bit. Her bikini bottoms were in the way, but I didn’t want to push my luck, so I went back down to her upper thighs, not wanting to stop yet. By this time her legs were apart a good deal, giving me a glimpse of her bikini covered pussy, the outlines just barely visible. As I was rubbing, I let my fingers lightly brush her pussy, and she began to breathe more heavily. By now I was getting more desperate, and was no longer concerned with trying to be sly. I just wanted to see and feel what she had under those bikini bottoms! I began rubbing her pussy through her bathing suit with my thumb, while my fingers began to play with her ass. She was pushing back against me, whimpering a little bit, and I slid my fingers up into her bikini. I was running one finger up and down the crack of her ass, and it found her little asshole, which I began playing with. She was pushing back against me, and I started to put a little bit of pressure on it and it began to go in just a little bit. We were both out of breath and totally involved in what was going on, when suddenly we heard the garage door going up. It was my stepmom home from work for lunch! We raced back into the house before we could get busted, and it was torture waiting for her mom to leave again…

To be continued…