I went to a dermatologist to check on some pre-cancerous sun damage, mostly on my face. She did a full-body exam, with me naked and an assistant taking notes. She paid no special attention to my uncircumcised penis.
Then she started telling me about skin cancers and what they look like. She showed me pictures of melanomas and non-cancerous spots. She described a particular kind of discoloration that needed to be watched. Then she asked if I had any questions. I had one.
"Can those discolorations occur on membranes as well?"
"Yes. Do you have one somewhere?"
"On my glans."
"Well, roll your foreskin back so I can see."
I did so, and turned my glans so that a small, darkened area, like a big freckle, was exposed.
She gently took my glans in hand and studied the discoloration.
"It doesn't look problematic. Just keep an eye on it and let me know if it changes or becomes itchy or painful."
I know it would be creepy to get off on this, and I would never put a medical professional in the position of stimulating me sexually. But hearing a woman say "Roll your foreskin open" keeps echoing in my head.