I remember at the age of eleven or so, the first time I had an exam for hernia. My doctor, a middle-aged bald man who'd been the family M.D. since I was a small boy, put on some gloves, sat on stool and for the first time, told me, "drop your pants." I wasn't sure what for, but I unbuckled my belt, unzipped, and let them drop, leaving my white briefs in place. He matter-of-factly said, "Shorts, too... I need to do a check for hernia." This was definitely a new experience for me... and I still had no idea what he was talking about. But the feeling of being ordered to strip completely naked from the waist down was strangely thrilling as well as embarrassing. So I slid down my underwear and let him come in close, breathing through his nose (I still remember how cool the air conditioning in the room felt on my penis.) I was surprised, but didn't move, when I felt him put his fingertips on my left testicle, followed by the traditional (but new to me) order to cough.
I don't get turned on by men, middle-aged or otherwise, and I didn't then. But there was something about the experience of someone completely dressed (male or female), ordering me to strip and then examining and touching my privates, that I enjoyed the very first time, and every time since, male doctor or female doctor.
My current doctor has me lie down on my back on the examination table, undo my belt and lower my pants just enough to palpate me (I always enjoy this), and then does the prostate exam before the hernia check. I still enjoy it when I hear the words, "Now please stand at the end of the table and drop your pants."
I think I enjoy pulling down my own underwear as much as I would enjoy the doctor pulling it down.