My sister is two years older than me and very extrovert. A few months ago, we were watching a late-night film on TV one Friday night, which was quite sexy and had some good-looking women in. When it finished my sister said 'So what are you going to do now?' I said I was going to bed, it was after midnight. She said, 'What else?' 'Nothing, go to sleep' I said. I knew what she was thinking but I was a bit embarrassed. 'You're not going to have a tommy tank then?' (that means wank, in other words masturbate, here in Britain). I went red and said nothing so she guessed the answer was yes. She said 'How come your bed squeaks so much at night?' I still said nothing. 'It's nothing to be ashamed of. I do it too.' This surprised me because I had never really thought girls did it. 'Next time I hear your bed creaking I'll tap on the wall and we'll do it together'. Then I made an excuse and went to bed, red as a beetroot but very horny. But that night I wanked in the bathroom.
A few nights later I was wanking in bed and I heard this knocking on the wall from my sister's room. I felt embarrassed but excited as well. My heart was thumping. I carried on stroking my cock but more slowly. After a few minutes there was another tapping, then I heard her sort of sighing quietly. It was just as she said. The sighing continued for a bit then stopped and I came.
Next time we were alone together I knew she was going to talk about it again. I really wanted to talk about it but was embarrassed, but once we started talking I was glad we did. She said that she wanked regularly and I said I did too, nearly every night. I asked her how she did it and she said rubbing her pussy and clitoris with her fingers, but she wanted to get a vibrator. I told her how I did it. Then we talked about lots of things to do with wanking and sex, and I got over my embarrassment of talking about it to her. A few weeks later we were watching tv and our parents were out. I was pretty horny. She was on the sofa and I was in an armchair. Then she started playing with her tits, just as if I wasn't there. First she rubbed them through her t-shirt, then she put her hand up her t-shirt and played with them. My cock was bursting but I didn't dare to touch it though I was dying to. I could tell she loved teasing me this way. Eventually she put her hand on her pussy and started stroking it, then undid her jeans and put her hand inside, glancing in my direction occasionally. I made some comment like 'you seem to be enjoying yourself'. 'Why don't you have one too?' she said. I said our parents might come back any moment and how would I put it away in time? She said we would hear the car and I would have plenty of time, which was true, but really I was too embarrassed to get my cock out in front of her, even though I wanted to. I couldn't see much, it was all under her clothes, but her hand moved faster. I could tell she was getting really turned on and she started breathing heavily. Then she giggled and said 'I'm going to come'. And the breathing got louder and became sighing and she came. Then I went to my room and came off straightaway. It was the horniest thing that's ever happened to me. I hope I can get the courage to wank off in front of her, because that's what I really want to do.