During a summer evening at a friend's place with several other friends, after eating, we were offered to go into the hot tub. No one knew that our friend had such a massive hot tub, so we went in with our underwear since we didn't have swimwear. At the time, I didn't yet realize that I was gay, but I clearly felt an attraction to one of the guys who was with us. He was small, tanned, with well-defined muscles... Let's just say I was quite aroused underwater, luckily the bubbles hid it all!
After a while, we got out of the water. My best friend and I went to the bathroom to dry our wet underwear. We did our best with towels and then with a hairdryer, but it's not very practical when you keep your clothes on. My best friend took the lead and removed his boxer in front of me. He's a pretty self-assured guy, and I avoided looking as I didn't want to make him uncomfortable. But it was the first time I saw him naked, and the temptation to glance at his equipment was quite strong. I stayed focused on my mission: drying my soaked boxer. Then, he wrung out his boxer in the sink, and a lot of water came out. Normal, you'd say! So, I did the same, removed my boxer, and did as he did, not thinking too much about the fact that it was also his first time seeing me naked. Then, as I was wringing my boxer, he seemed shocked and said, "Damn! Dude, your dick is huge! I thought mine was already big, but yours is just gigantic!" At the time, I knew I had a decent size, but to think of it as gigantic... my only size references back then were from porn, and we all know that porn sizes aren't "standard"! Ha-ha. So, of course, you can guess, I looked at his dick too and said, "Oh, you think so? Yours is not bad either..." I didn't know what else to say. Ha-ha. I should also mention that when I'm not erect, it's relatively large by default, and in the hot tub, I had a significant erection while looking at my other incredibly sexy friend. So, my best friend clearly saw the most impressive version of my non-erect penis.
We went back to the other friends, and I thought he probably wouldn't bring up the topic. He knew I was shy and liked to stay discreet. Unfortunately, I shocked him more than I had imagined. He started talking about it with the others, very proudly. I found it very embarrassing but also quite validating. Ha-ha. Later on, the rumor spread to various friend circles. I officially became the shy and discreet guy with a huge cock, and it actually helped me come to terms with my homosexuality and enjoy it.