There was a guy in my neighborhood that joined us frequently at my friend's dock for a swim in the bay during the summer. We would all dive or jump off the dock and swim all day long. He was very fit, and the only one who wore a brief swimsuit. It was dark blue and made of a knit fabric, not lycra or nylon. The leg openings loosed up during the day, and as he moved, we could see the side of his balls and his pubic hair sticking out. He knew what he was showing and ate up all the attention of us trying to stare at his crotch without him catching us. He knew, though. I saw him smirk several times. It was a big time turn on for me.