Definitely a play doctor here. 36/m. With an openness for both clinical and sex/erotic exams.
To me, it's definitely the incredible combination of having total control...the patient's nervousness, embarrassment, and uncontrollable arousal...and the aspect of taking your time with the whole examination.
Of course, the control and power part is obvious. The patient starts clothed, but must continue to peel each piece off, as the exam goes further and further. Rarely does an exam start with the patient nude or even in underwear. And the whole time, I'm clothed. Just a subtle piece of power. And then, the patient has no choice but to listen to the doctor's orders, because it's what's "best" and "needed". The patient does as told, because they have to...and really, because they want to.
Second: the patient has those three feelings. Nervous, not knowing what's coming next. Will the doctor check "down there"? Or " back there"? Wondering if they will "get hard" and will the doctor notice? The heart starts to race and beat faster...and inevitably, the erection comes. Then the embarrassment hits. The heart races faster...and the more the brain thinks about it, the harder the patient gets. That factor of uncontrollable arousal that can't be fought. Pre-cum. A wet spot. The patient has no idea what to do...
And then the door opens...and the doctor enters...
Leading to the last piece: the doctor gets to take his time. Make the exam last. Checking the vitals, the ears, nose, throat. Asking questions. Embarrassing questions. The shirt comes off...checking the heart, palpitating, pressing and prodding. Leading to the inevitable fingers-in-the-waistband. And well, it goes from there. And it goes on and on. Genital, rectal, enema, samples, and on and on...and if it's a sexual exam, all bets are off.
That's why I love being a play doctor. Just so much fun, haha.