This happened to me on a Greek ferry traveling between two islands a few years ago. I was with my girlfriend, Val. It was afternoon, and we were catching a nap on the side deck of the ferry, up towards the bow, in a kind of cul-de-sac. We were both lying on our backs, side by side, on our bedrolls. I was wearing only my silk running shorts (and a pair of Marks and Spencer briefs), Val had on shorts and a tank top.
But enough about Val. She napped through the whole thing.
I don't know why I opened my eyes, but when I did the woman at the rail quickly turned her head away. She was maybe 25 years old, in trim short shorts and a tank top herself, and she was leaning against the railing a few feet away from me, from my feet, that is.
It was the way she was leaning: with her hands on the top rail and her feel planted several feet away, so that her back was more or less level with the deck. Actually, her back curved down from her bottom and then up again to her shoulders. I noticed that her skin was exposed at the small of her back and her belly, where the tank top was rippling in the breeze.
She had long hair, and that too was blowing around. She was wearing sunglasses and looking out to sea. But i felt sure she had been looking at me. She hadn't been there when I closed my eyes. No one else was close by, though there were some other passengers further away at the railing. But a low steel triangle beyond the girl slightly blocked them from my view.
I thought I might be imagining things, but I suddenly felt very turned on. Her pose, if that's what it was, was provocative, as if she was inviting some stranger -- me? -- to take take her from behind while she held on to the railing looking out to sea. I was tanned and fit and feeling sexy myself after episodes with Val that I have already written about. The idea of showing myself off to a woman ten years my junior while my girlfriend slept beside me appealed to me. I put my hands behind my head, provocatively, stretched a little, and closed my eyes again.
But my heart was beating and my mind was rioting. And that can produce physical changes in a man. I felt myself twitch involuntarily inside my shorts, inside my briefs, to be precise. It happened again. I was going to get an erection whether I wanted to or not. I decided I wanted to. I'm sure the movement in my shorts must have attracted her attention. I kept my eyes closed and imagined her looking right at the shape in my shorts, which only excited me more.
But there was a problem. My briefs were confining me. I could feel my prick straining against them at an awkward angle. There was only one solution. Still with my eyes closed, I reached down my right hand and straightened out the situation inside my shorts, in one quick liberating motion. My stiff shaft surged past the elastic top of my briefs. The swollen head pressed up against the silk of my shorts, below the waistband.
I took a peek, and once again I caught the girl's head turning away. I felt very exposed: the knob of my cock was pretty clearly outlined against the silk, and the beating of the blood in my body meant that it wouldn't sit still, but pulsed like a throbbing vein. I covered my eyes with one forearm, like one of Michelangelo's slaves. But I could peep out below my arm and see the girl's legs, and ass, and smooth tanned tummy without being seen to do so, and she could be free to watch me without fear of being detected.