I will agree with many of the previous posters; for me it has to be realistic. Of course, there are limits to the level of realism I can achieve since I don't have an actual clinic with a full exam room, but wherever I play, I do my best to replicate that environment as closely as possible. As for the procedures themselves, it's okay if they're very rare in actual practice, but they at least need to make some sense clinically. I can think of numerous things from my play exams in this category. For example:
1) Taking a rectal temperature on a healthy adult patient
2) Using more than one speculum per exam
3) Doing a pelvic exam in the knee-chest position
4) Doing an anoscope or proctoscope exam on an asymptomatic patient
5) A doctor taking the time to administer an enema from a bag
6) ...Or for that matter, a doctor spending more than 30 minutes with a patient at all!
Other things like stething over the genitals (as drjmc78 mentioned) make no sense at all -- although I could potentially see auscultating the femoral arteries, which would be close by. Anything that results in the doctor's clothes coming off is totally out, too.
That being said, if you enjoy highly sexualized medically-themed fantasy play, go for it! Not everyone enjoys what I enjoy (and vice versa).