That once I've become an adult and every year following, having it standard practice for me to be only in my underwear, no gown, though I opt to wear a jockstrap instead of underwear. The standard procedure is that I lie back on the exam table, when asked by the doctor “Can you lie back for me” or something like that. To be examined starting at the neck, working his/her way down to liver & kidneys . Then maybe moving my pouch around a little to check for potential rashes caused by my jockstrap, and physically assess the pouch and assert it's a good size for my genitals and not too tight, etc. Then to tuck one arm under my body to signal my body to raise for lowering my jockstrap down to my knees in order to examine my genitals.
Then to start with checking for hernia, perhaps explaining that patients can't always tell when they have them, thus the importance of the doctor to check. Followed by a careful physical assessment of my balls, checking for lumps, and also asking “does this hurt”, etc as they palpate my balls and around my scrotum, to make sure there's no damage that I may not be aware of (and not assume that I would be aware if there were something wrong)
Lastly since i am an adult, verifying that blood can flow to my cock by working a medically related palpation technique in a way to determine that my blood can effectively flow in that direction. Maybe the minimal extent of determination is that I start to get a semi, and don't “need” to get all the way hard, unless a patient complains about difficulty geting erections. To which, a more intense study would be performed to determine if the blood has potential to flow properly.
And just like sometimes when you have a rectal exam and they see the opportunity to get a stool sample to examine it, if they see you get a full erection and seem horny enough, asking you if it is ok (or if you want to) to extract a semen sample to test for fertility as an option, no cost to you, that they can do. This way if the exam makes you horny, they can take care of you right then and there, with the understanding that “it's normal”, just like they tell you when they see you have an erection during the exam.
Maybe during this procedure, it is also part of the procedure for them to restrain my arms and legs to the table for their own safety, to make sure I don't kick either voluntarily or involuntarily, and that I don't become aggressive, especially if the doc is opposite gender. And perhaps a little psychology of not leaving there with guilt, because I was tied down and not in control of how I was examined.
And perhaps once i lie back, it is standard practice to place a blindfold on me, to mask how my eyes look during the exam to preserve the patient's dignity, and to preserve their dignity from being seen / watched as they physically examine me.