When I was younger, my older sister had just turned 16 one summer and my parents decided she was old enough to watch both of us during the day when they were at work. I have usually gotten along with her pretty well, and we were both pretty open about things.
One morning when I woke up, I walked down to my sister's room, and when I walked in, she was lying naked on her bed looking at a magazine. I asked her why she was naked, and she said it was hot in her room and she could lay around naked if she wanted to. I just stood there for a few seconds and she asked me if I was just going to stand there all day, so I went back to my room. I felt a little lonely, but I decided to do it since she did, so I took off my jammies and went back to her room naked as well. She asked me the same thing I asked her, and I told her I just wanted to go naked too, and she didn't have a problem with it. We hung around her room for a little while listening to music and reading teen magazines, but after she looked at some magazine with lots of boys in it, she asked me if I would go downstairs and watch some TV for a while. I asked her why, and she told me she wanted to masturbate. I gave her a clueless look, and she acted surprised and asked me if I ever masturbated before. I hadn't even heard of it, so I told her no. She then said I didn't have to go and she would show me, as long as I didn't tell mom and dad.
She sat up and leaned back against her pillow, spread her legs apart and started rubbing her hairy vagina. She told me everything she was doing and feeling the whole time, and I watched her closely, almost like I was studying. She was still a virgin so she could only push in her finger a little bit, but every time she did she let out a small moan and breathed heavily. When she came, she gasped and stiffened up and then rolled onto her side, rubbing her hands and legs against her sheets. I asked her what happened and she said she came and then said it was my turn.
I leaned back and spread my legs too, exposing my little pussy to her. I had a little bit of hair, but it was nothing compared to her big, woman-like bush. I tried doing everything she did, but it was kind of uncomfortable. She then reached out and rubbed me a little bit in the right spot and asked me how it felt, and I said it was really good. Then I knew what to do, so I started rubbing my lips and tiny clit, and it did feel much better. I couldn't get a finger inside me, so I just kept rubbing in circles on the outside. After a few minutes I told her I had to pee, but she said I didn't and to keep going because it is about to feel so, so good. My hand kept going and the tingling between my legs kept getting stronger, and then it happened. It felt like an explosion went off in my vagina, and I squirmed around and squealed. I actually cried a little bit because it felt so amazing.
She asked me what I thought, and I said it was the best thing I had ever felt. She told me that's what masturbating was, and that I can do it any time I wanted, but in private. We got up to go downstairs, and I jumped at her and hugged her tight, thanking her over and over again. She hugged me back and led me downstairs and made us some breakfast. We stayed naked and when we were watching TV, I asked her if we could masturbate again and she said sure, and we did it next to each other on the couch. She didn't do it as much as I did, but I must have masturbated six or seven times that day, every time there with my sister. The last time, I was right in the middle of it when the garage door opened. We both ran upstairs and threw some clothes on, but I went ahead and finished what I started before I came back down.
I don't think I had ever felt that close to my sister before that day.