My cousin Kathlyn and I grew up together as we lived nearby and our family spent a lot of time together.
As far as I remember sleepovers were quite usual, mainly on weekends and holidays. As little kids we used to play and do all kinds of stuff together. Quite often we bathed, dressed and slept together.
As we grew up, we remain very close, hanging out with the same group of friends and still having sleepovers from time to time. We were always pretty much comfortable around each other, even if we were only in our underwear. The difference was that now, at 19 years old (I was 18), Kathlyn was no longer a little girl. She was now a 5'9 curvy young woman. She was rather pale, with long dark brown hair with a perfect sized round ass, nice thighs and great boobs. Her face was quite normal, but her body was great, maybe because of all of the dancing she did as a hobby.
This one time, I was spending a few summer days at her place. It was very hot outside so we stayed home, but with no AC, it was hot inside too. Trying to fight the heat, I laid in the floor in front of the couch with a pillow under my head watching MTV. Soon after Kathlyn came from her room wearing only a long white t-shirt and as she walked by me to go to the kitchen I got a clear view of her big ass. I had seen her before in her underwear but this was different. It was like voyeurism and I liked that. She went back and forth a few times, and as I was laid in the middle of the living room she either had to go over me or around me. Either way I could see that semi-exposed moving ass and it got me a little excited. It was when she came back to the living room that I caught even a greater glimpse, as she reached over the other side of the dinner table to grab a magazine and had to raise a leg in order to reach it. Her t-shirt moved up and her panties were now a little bit insider her ass and I could clearly see the edges and shapes of her meaty pussy! My dick got so hard I had to cover it with another pillow avoiding getting caught.
She sat in the floor across me, with her back against another couch with her legs bent to support the magazine. She began to make small talk, commenting on articles she was reading. I responded as well as I could, trying to not let her know that the way she sat across me and the way she positioned her legs gave me an even better view of her pussy barely covered by her small white cotton panties! I could see shapes and forms. No pubic hair in sight as it seemed fully shaved pressing the fabric. Even I had, from time to time, admired her looks, I had never ever thought of her with lust!
A while later my aunt arrived home carrying some groceries. Kathlyn and I got up to greet aunt Arabel at the door and help her with the bags. Aunt Arabel was a 36 years old 5'6 tanned brunette with a great body and she always dressed in a way that was almost impossible not to notice her large ass and big boobs. So when she complained about how hot it was and announced that she was dying to change her clothes, was no surprise to see her returning from her room with a very short dress. I was now with my aunt and my cousin, both wearing short clothes, no bra and barefooted!