When I was 16 I visited my GP, (the Dr who gave my very first Nude Physical aged 13) and was my head Dr until he retired (and then passed away)
By that time I already had realized that instead of feeling terribly embarrassed as it happened during the early ones I enjoyed Nude Examinations. That day he was with another young Dr, probably in his mid 20s, he was a bit shorter than me, curly blonde hair and with a thin Moustache, a pretty nice guy. It was the first and only time I get to see him in my life. I think he was assisting my Dr, in a way of learning how to conduct examinations. It's more likely he had gotten his Degree during the prior year.
After the Dr asked a few questions, he made me strip to my undies, I was wearing Pale Yellow Briefs, and the minute I dropped my Pants I was already hard, so although I'm not that well endowed it was pretty noticeable. My Dr commented to the other "it seems he's always like this" and the young man smiled and looked my boner. It was a kind of follow up examination so it took about 20 minutes. When the Dr made me lower my Briefs I was fully erect, with my Penis laying on my belly. He made a little joke about it and the young Dr laughed as his face blushed a bit while staring at my Junk. I think he was kinda enjoying the view and I could swear he had a hard on as well (he was wearing light brown pants with a White Coat, the same all Drs wear but it was shorter, a little bit below the Waist line, and unbuttoned, meaning open) of course I can't Guarantee 100% he had an Erection, but you could see a little bit of "swelling" in his pants, I think I saw the outline of his penis placed to the right, and it was not my imagination. He's reaction, specially the Blushing of his face, surprised me a lot (but I loved it) after a quick observation of my Penis and Testis, my Doc said I could get dressed, and not long after that I left. I really enjoyed the whole situation, I assume the young Dr perhaps felt surprisingly aroused (if he did) by seeing a Nude Teen boy with a raging hard on, maybe it was the first time he did. For me was a great experience and now this Topic brought all that "Sweet memories" back