I kept this a secret until now, but reading your stories I wanted to contribute. Great site!
Me and my friends always used to rate girls at school, on legs, breasts, ass etc., but there was one girl who was like a model, a year older than us, called Hayley. She was about 5'8', long dark hair and olive skin, with a great figure.
Anyway, her mum and mine worked together, and she took me round her house one day. I can't remember why, but needless to say it was a better choice than staying at home! So it was slightly disappointing to discover her mum appeared to be home alone.
I was watching tv while my mum chatted, and asked to go to the toilet, and Jenny (her mum) said, 'Yes, just go on up, Hayley should be done by now'. I tried to hold back my grin as all kinds of thoughts went racing through my mind. I got to the bathroom door and heard the shower click off, and I tried my luck with the door but it was locked. 'Who's that?' she said, 'Sorry, I just wanted to use the toilet' I said. 'Hang on'.
A few seconds later she opened the door holding a towel round her, Christ she looked real sexy with her hair wet. I went in and all her clothes were on the floor, I actually got a hard on while I peed! I opened the door and she was still wearing the towel, but a lot lower now and I could see most of her breasts. I was staring but I didn't care, her netball kit was the least I'd seen her wearing before! She smiled and said 'You wanna see the rest?'. I was frozen to the spot but she pushed me back into the bathroom and sat me on the toilet seat, letting the towel drop further to reveal all her tits.
I just stared at her small hard nipples and nearly came then. 'Bet you wanted to see these for ages' she said, and I just nodded. She shut the door behind her and said if I showed her my dick she'll drop the towel completely. I couldn't get my shorts down quick enough! She had a small triangle of dark pubes, and a shiny wet fanny which she started rubbing, with one leg on the chair by the bath. I started on my dick, told her I was about to come and she said, 'Let me'! As soon as she touched it I shot my load, some of it going on her leg. Then we heard one of our mums coming up the stairs so I pulled my shorts up, she put her towel back on and stood outside the door, and I shouted 'Just washing my hands!' as her mum got to the top of the stairs. Just got away with it!.
Sadly they moved away shortly after that and I had to wait two more years until I did it properly with a girl, but the thought of her naked still keeps me going!