A woman

You're extremely shocked to see a woman enter the room, but not as surprised to see that she doesn't look any older than the nurse, and she has a cute face as well!

"Where's Dr. Sullivan?" You ask.

"Wow, you've been gone for a while. He retired two years ago. I took over his practice. I'm Dr. Chase." She explained.

You flush as you realize she is going to examine EVERY part of you, but you try to put that though away as an image of her holding your penis appears in your head and you feel your cock rising to attention under the thin gown. You adjust your position as she tests your reflexes and examines your mouth. You dread the next part, which is when the doctor has you "turn your head and cough".

Her hand gently cups your naked balls and you quickly cough to get it over with. The sensation causing you to become even more excited. However, her hand lingers just a second too long, since it was at this moment that the door opens...