When I went for my happy 50th birthday colonoscopy, the anesthesiologist was an a guy I new from the club where I play golf. After he gave me a mild sedative, and they rolled me on my side, he leans down with the gas mask in his hand. Just before he put it over my face he whispered "you know, it's not uncommon to get an erection like this". I said "I don't have an erection" and he smiled and said "I wasn't talking about you" and placed the mask over my face. I thought I had a warped sense of humor.
Randy