When I was much younger (probably best if I don't state exactly how young!) a female friend of mine would often invite me over for a swim in her pool after school. Having gained permission in advance from my parents, I would take a pair of swimming trunks in my school bag in the morning and then after school would meet my friend at her home. My friend's mother was an attractive woman in her late 30's, and she would often sit in a lounger beside the pool and read or talk to us as we splashed around. She was a flirtatious sort and would embarrass her daughter with comments about how nice I looked (this is not bragging on my part! This is simply how this woman was ) and although I took it as harmless teasing I couldn't help but be pleased that this woman payed so much attention to me. In truth, I found it somewhat sexy. One afternoon I arrived at my friend's home to find that she had been delayed at her choir practice, and I was told by her mother to change into my swimming trunks and wait by the pool. I changed clothes in my friend's bedroom and went out to sit at a glass patio table beside the pool, and as I did so I heard a whistle from the kitchen window. It was my friend's mother, of course, cutting up and making the 'OK' sign and winking at me. This was funny, of course, and I laughed as she had intended me too, but it started a train of thought in my head that wouldn't be derailed: What would her reaction be if I gave her a real reason to gawk? There was no internet in those days (dating myself!), but I had been made aware via other media that there was such a thing as 'flashing' and I was intrigued and aroused by the idea. I was sure that she would be joining me by the pool within a few minutes, and I was struck by a sudden inspiration: The trunks I was wearing were quite loose in the leg but short, and if I slouched slightly in the chair and adjusted a bit...there. The tip of my penis, which had lengthened a bit while contemplating this daring idea, was now plainly visible, protruding alongside my left thigh (I'm making no assertions to extraordinary length or girth here, the trunks really were quite short). I could feel my face flush, and my penis twitched and expanded further as I thought about what she would see if she happened to look down through the glass table-top. And here she came, smiling and with book in hand, prepared to spend the late afternoon sunning, reading her book, and observing her daughter and I swimming and playing in the pool. She sat down opposite of me at the table, and began to tell me that her daughter would only be another half-hour or so at choir practice, and as she put her book down on the table she looked down... ...and her words faltered, she stuttered, she said "Um..." and then forced her eyes up to my face again, and I knew with certainty that she had seen my bare penis pressing firmly against my upper thigh . I had to suppress a nervous bark of laughter, because to do so would be to give the game away, all pretense of innocence on my part lost. Instead, I made small talk, "That's cool, and thanks for letting me wait", blahblahblah, and she responded in kind, smiling, saying "Well no problem hon, you're always welcome" yadayadayada, and we chatted about my school work, the camping trip my class had made recently, her daughter's choir...and every few seconds, her eyes would dart down to look at my penis. I think you'll understand that all of this was a form of heavenly torture, the risk of being shamed mingling with the sharp sexual sting of this self-dare. My penis was throbbing now to the point of discomfort, but I didn't dare change position without making it obvious. And then, saved literally by the bell. The phone rang in the kitchen, and she had to leave the table to answer. As she departed across the patio to the back door I eased my sitting position, and nearly on the heels of this my friend arrived home. My raging erection subsided quickly, and within ten minutes my friend was changed and we were in the pool together, and her mother sat as she always did, book in hand and enjoying the late-afternoon sun. When I got home later, I locked my bedroom door and masturbated twice to jerking, spasmodic orgasms, my toes curling and my semen fairly spraying my bare stomach as I thought about what I'd done.