Matt, I had one this Monday and am still waiting for the results. Maybe today. In my case it's a follow up after an injury.
It didn't take long. The very nice female techincian took me to a small quiet room and instructed me to undress from the waist down, put on a gown, and lie down on the bed. When she came back, she put a blanket over me, handed me a towel and had me pull up the gown and grab hold of my penis with the towel and keep it out of the way. She then handed me a rolled up towel and had me loop it under the scrotum and hold it securely. This supported the testes from underneath. she then did the exam as described by others. It took about ten minutes. All she saw was the scrotum itself. Not bad at all.
Dave