My father is a doctor. When I was fifteen years old, I thought that I wanted to be a doctor too. By then, I was masturbating frequently. In those days, pornography was not readily available, but I made do with my father's medical textbooks Of course, I desperately wanted contact with girls, but I attended an all-boys high school and girls were not readily available for a fifteen year old.
My sister was twelve years old and starting to mature. When she wore a tee shirt, I could see her nipples and the beginnings of breasts. I started to think about her more and more, remembering the childish doctor games we had played when we were much younger, masturbating to the memory. Then, I began to wonder if she would do something like that again. I spent more and more time with her, following her into her room, hoping to catch her dressing or undressed. The most that I saw, though was her in a tee shirt and cotton underwear, a pronounced mound between her legs under the panties. That sight made me nearly frantic to see more and I had to do something.
Thinking back to the doctor games, I devised a plan, waiting until our parents were out for the evening to put it into effect. I had on an unbuttoned shirt and a pair of gym shorts. Putting one of my father's stethoscopes around my neck, I walked down the hallway toward my sister's open door, the light from her room spilling out into the hall My heart was pounding so hard in the quiet that I thought I could hear it. When I came to her door, she looked up from her book and saw me standing there with the stethoscope around my neck. 'What are you doing with that,' she asked.
'Nothing,' I said, 'Just listening to my heart, it's interesting, would you like to listen?' When she agreed, I put the stethoscope around her neck, opened up my shirt and told her to go ahead She did, moving the little disc around my chest while I sat on the bed in front of her. When she finished I took the stethoscope back and asked if I could listen to her heart. This was it and I could hardly breathe, our eyes met, she looked at me for a long time, then nodded slowly. She had on a long nightgown that modestly buttoned up the front, all the way to her neck. 'Why don't you lie back on the bed and unbutton the top few buttons?' I said, 'I can't listen through the cloth.'
'Okay,' she said, 'But turn off the light.' Which I did, but I could still see her in the half-dark, the top of her nightgown now open.
She lay back with her arms at her sides, as I carefully placed the instrument on her bare skin, moving it around and pushing back the nightgown a little. Approaching her nipples, then touching them a little, then a little more until I could feel that they were becoming hard and erect. She didn't protest, 'Can I touch them with my fingers?' I whispered, and she nodded. I did, rubbing them lightly, feeling the nipples between my thumb and forefinger, pushing the nightgown back until I could see them, standing up pink on the light pink mounds. My sister's eyes were closed, both of us were breathing hard, my penis was hot and hard in my shorts. 'Does that feel good?' I asked.
'Yes,' she said, 'It does.'
By then, I couldn't help myself, I unbuttoned a few more buttons on her nightgown and slowly began to rub my hand down over her stomach, to the top of her pubic mound She didn't protest at all, instead she parted her legs slightly, inviting me to continue. I moved my middle finger down over her clitoris, between her small labia, pressing slightly into the vaginal opening, then bringing the slippery wetness back up to her now more hard and erect clitoris. Rolling it back and forth, up and down, under my finger, faster and faster. 'Yes,' she said, 'Yes, yes.' Pushing my hand aside she replaced it with her own, opening her legs, raising her knees, her finger working from her anus to her clitoris.
At this, I pushed my shorts down, my penis standing straight up, hot and slick. I began to jack off, watching my sister doing the same. I guess that we reached orgasms at about the same time, my semen spurting in throbs onto the bed, while she just laid back, her legs flat on the bed. We didn't say anything, we just looked at each other. I was thinking that she must have masturbated before, wondering if she had been thinking about me in the same way that I had been thinking about her.