I usually do not become aroused when being examined by female doctors. However, my first time with a female doctor was quite different. Previously all of my physical exams had been done by older male doctors, I usually undressed to my underwear and only sometimes were my genitals examined.
At age 29 I had a physical for after having had surgery a few months previously. The nurse handed me a gown and told me to remove everything including my underwear. I knew the doctor was going to be a woman but I was surprised when she walked in because she was very attractive and about the same age as I was. I wondered how thorough the exam would be, and I started to become aroused while she was examining my abdomen. At this point I was lying on the table with the gown draped across my lap.
She then sat down on a stool and asked me to stand in front of her, and would I please leave the gown on the table. I stood naked before her, now fully erect, and attempted to hide my penis behind my hands while she examined my testicles. She then told me that she would like to examine my penis, very matter of factly, and I reluctantly moved my hands to my side. I'm sure she could see that I was embarrassed, but she did not seem to mind at all. Not that I was ashamed of being seen naked and erect by a young woman, but I did not want her to think it was in any way intentional. She let me know with her relaxed, friendly voice and her smile that she did not take offense.
After she checked for hernia she asked me if I had ever had a rectal exam. I said I had not. She said that she was going to do one, could I please turn around and bend over the end of the table and spread my legs. As I complied with this request I just imagined the view she must have had, it occurred to me that no one had really seen me that way before, and I remained fully erect the whole time.
She warned me that it would feel a little uncomfortable, but as I felt her finger entering me I realized it was not only not uncomfortable but actually a pleasant sensation, and when she found my prostate I could not believe how good it felt. The sensation in the tip of my penis was incredible and if the exam had lasted much longer I think I would have had an orgasm. To this day I find rectal exams pleasant and wish they lasted longer, but that was by far the most pleasurable and exciting that I have had, because I was erect at the same time.