From time to time I remind myself of some situations and I post here.
This happened when I was about 16 years old. We lived in a big city in a house where the balconies of the different flats were divided by just a thin 'wall' made from the milk glass and you could see through the crack between it and the facade of the building. I had a friend in the neighbouring flat, she was the same age as me, we grew up there and our relationship was changing dramatically that time, even it didn´t turn her to be my girlfriend. She was very pretty, the girl next door kind.
We spent a lot of time chatting on the balcony, each on their own side. One morning during the summer holidays I had a friend who visited me and we played some music (we both played on the guitar) and some computer games. I went to the balcony because she was there and after some short time to my surprise I found she was wearing just a T-shirt and no pants. It was incredibly arousing. And funny now, but the only idea I had at the moment was I asked her to wait a second, went to the living room to ensure to myself that my friend is playing a long lasting game, got half naked in my room and went back to the balcony wearing the T-shirt only, exactly as her. We continued talking but soon it was very obvious I had an erection and I started to touch myself a bit. She didn´t find out this time but my computer friend who paused the game came in a while to ask me for something caught me talking to her while naked. He only saw my butt, but anyway I was in a trap, if I turned he would find out I had the erection and if I stayed with no move it would not be understandable. My horniness obviously wouldn´t go away so finally I had to capitulate and turn to his side and quickly run into my room (the one the balcony belonged to). He started to laugh noisily when I just sat on my bed covering myself with a shirt, but he stopped when I told him she was naked that way too and that he just broke something that could surely lead to my first sexual experience. He asked me if I plan to jerk off and since we saw each other masturbating before and I was so horny at the moment, I just started to do it right there and he joined me. Then we moved to the computer and did it together watching to some porn and I came very quickly. He also admitted this was very arousing situation.
Next day my friend came again, because it was planned long ago, but I asked him not to disturb me if anything similar happened. I went to the balcony wearing just a very long T-shirt. She was there with a certain smile on her face and when I asked what was going on, she told me we forgot to close the balcony door last time and she heard everything. There was nothing special in it and she was not shocked she later told me how she caught her younger brother jerking off with her underpants...) but I turned red anyway. Then she did some move and was holding pants in her hands to show me she is naked and I almost came without even touching myself. I tried to look at her closer, but I only found she was shaved on the sides leaving the small area of cute blonde hair. Then she hid herself quickly. She asked me if I would show her mine, I wanted to but I was just little afraid I would ejaculate involuntarily, just because of her watching me. But I did and she liked it, because till then she saw only her brother. She asked me whether I needed to finish it and I answered definitely yes. At that moment I could not resist, I just touched my penis and came in front of her, which was terrific. This lead to some interesting events with her (I may write about later), we never slept together nor were wanting some serious intercourse. I liked her, but she wasn´t exactly my type and so was I too her. We were the great friends and taught each other a lot (not only in sexual way).
I don´t know whether my friend was watching us or not, but when I came back to the flat he was in the bathroom and spent quite a time there.