I call myself curious I guess because I'm not attracted to men in anyway other than I found I got on better with them from young but also that I enjoyed seeing others erect and I have always become easily aroused with other men and usually when and where least expected, I must admit I even became erect swimming my my uncle, textile swimming!
I must admit I even became erect swimming my my uncle, textile swimming!
Assuming that it wasn't because your uncle wasn't turning you on, I think it's because any sort of new or pleasurable sensation on your penis often brings men to erection. It can even be a cool breeze or the sun suddenly coming out on a sunny day. I wish that was something that more women, and more men who are less sensitive to that sort of stimulation, would understand. As Freud said, "Sometimes a cigar is just a cigar." Likewise, sometimes an erection is just an erection.
Women with sensitive nipples experience the same thing. Sometimes it means they're turned on, sometimes it just means that their nips are cold. Since nips are smaller then penises, the condition isn't as conspicuous, and since we often don't see women in such various stages of arousal, it isn't seen as such an issue.
I consider my self a straight male, with a wonderful nudist partner. I find myself becoming aroused when I see another male erect. We were walking on the beach when a guy walking towards us started to get erect. by the time he reached us he w as fully erect. I became erect looking at him. He stopped for a quick chat, we where admiring each other and exchanging pleasantries then we both went on our way. My partner asked me about it, but I couldn't explain it.
Well, funny thing about primates who are social. The males of human, chimp, bonobo, and many other monkeys get hard when they are aware another male is. Why? Because unlike humans, estrus is once a year and it is a competitive time, where many males may try to mate with fewer females and they are not always willing. So the evolutionary response to an erection which signals a rival is mating possibly, is to also become erect without thinking it or being aware of arousal. If you played team sports, two boners means lots of boners. It's a natural vestigial evolutionary trait. However, if you spent lots of time thinking about how suave and sexy he was, then maybe it's not that.
If you don't know why or how it happened chances are it's just your brain doing the things it knows to do.