When I was going to school at a US University I was studying to get my Bachelor of the Arts with a major in Drama. One quarter I took an Improv Class ("Improv" = improvisation. The Professor gives two or more students a general scenario & certain "actions" to play out. The students make it all up as the "scene" progresses.)
The class became really popular with about 8 of us core students - & at the end of the quarter we 8 & the Professor decided to continue Improv Work outside of class for our own "artistic growth". We met once a week for several months at different locations, some of them outdoors, some of them at a student's apartment - always a different student's apartment each time.
Since we were outside of the classroom environment, the work sometimes got more and more intimate, personal, and (yes) steamy.
I & another male were assigned a Doctor's Examination Office scenario. I was Patient/ other guy was Doctor. Someone asked, laughing, "Gee, so is Mark gonna get a physical in front of everybody now?" I shrugged, "That's okay with me, I guess, I dunno."
The guy whose apartment we were working in that night spoke up & volunteered: "Hey since this is Doctor/Patient, if you wanna strip down you can feel free to do that here." There was some tense laughter from the group. And more laughter - chuckling & giggling - when the Improv started and the "Doctor" said to me, "Ok young man, I need you to strip down to your shorts."
I could feel my face already getting red, & I answered, "Ok sure, no problem, Doctor." I undressed in total silence - you could've heard a pin dop - and stood there in only my briefs and socks. I was tenting my underwear. I was nervous & actually scared crazy, but you weren't allowed to "break" character or scenario, so I waited for further Doctor's "orders" to see where this would go.
The Professor conducting the Improvs, a middle-aged lady who we students all loved, said, "This is all ok - but keep it as clean as you can."
The Doctor guy had me turn my back to the "audience" (still sniggering & giggling a bit) so when he pulled down my briefs only my bare buttocks was shown to everybody. He was facing me a little off to the side however ("upstage") & could easily see my erection, which was as full & hard as it could be. He couldn't help laughing - but "examined" me as we progressed with the "scene". He & I maintained our positions throughout so all the others saw was my bare ass - fully and openly displayed, that was for sure. The "Doc" didn't handle my hard penis or balls, but he got a full detailed look. (Nobody else did that I know of.)
Once our improv conversation was completed and we'd met our assignment, the Doctor said I could get dressed - I did. This Improv was talked about among us students a lot, afterwards. The group was a mix of males & females, with the girls all straight and around half of the guys were gay (just a guess on my part - & the guys who I thought were straight were just as interested in the Improv as much as anyone).