Seen At Waterfall

In my early 30s I was dating a woman a few years older than me. Several times we went to a county park, an hour away from the city we lived in, with a large beautiful series of waterfalls around a rocky-sandy island one could swim to from either side above the falls. There were also lots of nooks and crannies around the rocks both on the island and on either side, where people could hang out. Once I laid down in such a nook with a small pool of water, sitting back to enjoy the view and feeling, and she lay on her front between my legs and pulled out my penis for a blowjob. I was worried someone would see us as there were dozens of people in the park, but she said "no one here cares," and this was indeed plausible as, while popular, it was a large rural park with an honor system for parking fees and no regular attendants or life guards (not needed, either, as the water was seldom more than 4 feet deep, and the falls just a few feet high, wide and pretty but not dangerously powerful).

Her blowjobs were actually never the best, and she could only occasionally make me cum (most often this happened when she 69ed on top of me, as her generous breasts would then lay excitingly on my torso and she could keep up a steady motion until my orgasm). But the situation was already exciting in its riskiness which helped. Then it escalated when I looked across the river to the island, no more than 50 feet away, and saw four very young ladies (perhaps 16-18) walking along one side of it toward the edge closest to us. They were all thin and wearing the skimpiest of bikinis; in short, they were ideally sexy, and looking in our direction. Honestly, I could not tell if they saw us, but I don't know how they could miss us looking anywhere in our direction, as absolutely nothing blocked their view. It only took a few seconds more for me to cum powerfully in my girlfriend's mouth. She swallowed it all, then after another minute lifted up so I could reinsert my massive erection into my swimming trunks. Whether or not those teenyboppers saw me, they gave me one the best orgasms of the summer.