Usually i'm at least wearing underwear, but more often i still have my pants on, belt undone and lowered slightly.
However, there was one time (the only time I can thing of when I was completely nude for a physical from beginning to end.) It was for a hospital admission.
Before you start asking, I'll admit right away. The hospitalized physical was because I had severe depression and suicidal tendencies. I was admitted to the hospital in the late afternoon, then had to strip and was in full site of the nurses station all night, (The room was situated in such a way that there would be no "casual passers by to see me.) no clothing, no door on the room or the bathroom, a metal mirror, and only a sheet on the bed. (again, I under constant observation.)
The next morning, I was given breakfast (I don't remember what it was, and, at the time, I didn't really care.) All the plates, cups, etc, were paper and the utensils were plastic. (Even so, they were still counted when my tray was collected.) a nurse supervised me while I shaved, (This was a military hospital, and they insisted that regulations were enforced) and I was given a robe and slippers, then lead down the hall to an exam room. The doctor came in, told me to remove my slippers and robe, and then gave me the whole nine. Complete head to toe, scoliosis check, complete neurological exam, gait check, full genital and rectal exam. Then he started to talk to ask questions (I was still nude.) Eventually, he told me to put my robe back on, and I was escorted back to my room. Only then was I allowed to dress and move out of the "suicide watch" room and moved into a room with doors. (still no glass in the mirrors, though)
I did not, at the time, find it erotic or exciting. Frankly, I didn't give a damn. Some time later, however, after receiving treatment, I thought back on it and now it is almost humorous.