I've never had an erection during a normal exam, but I have had to be erect for my female doc.
For a number of years I suffered from a tight foreskin, it was getting more and more painful until I was eventually circumcised at 22. That was when I was at university and we had a female nurse, who examined me to see the extent of the problem.
Later on, I had issues with infections in the small scars that remained from the circumcision. By now I was married and registered with my wife's female doctor.
I had quite a few examinations erect by her, before I was finally cut again and a large cyst removed, which cured the problem.
Yes, it was embarrassing at the time, but she sorted the problems. Worst at the time was the time my ex was present and adding more to my embarrassment by asking loads of questions. In hind sight this got her and me into Med Fet!
After that she used to attend all of my exams and check ups. Then when they ended, she started organising play exams for me, so she could carry on watching...
Now divorced, but I'm still a regular patient, often still with her old friends in the audience!
Can't be all bad then!