She makes Mark jack off and gives instructions

"Masturbate for me."

I felt immediate disappointment. Not even a handjob? She did say that she would fuck me eventually. Was that a joke?

I grasped my penis, slowly sliding my hand up and down. This was uncomfortable.

Still, I couldn't deny the sexiness of this doctor. Her large breasts were hidden behind her sweater. Would he be able to see them? Was it better that they were hidden, imaginary, theoretical? Was it better to want to see her breasts, and be excited by the mystery and potential? There was the possibility they would somehow disappoint me.

I noticed her making eye contact with me. I looked away. She laughed.

"No reason to be shy. You've done this before, right?" she said. Her right hand moved to my bare thigh.

"Probably a million times." I said.

"And is this how you normally masturbate?"

"Well, I normally do it with inspiration."

"What kind?"

I felt sheepish, but oddly confident. She was a doctor after all.

"Have you heard of JOI?"

"I'm not familiar" she said.

"Jerk off instructions. When girls tell me how to do it."

"So you want me to tell you how to jerk off?"

"Please."

"Very well. Start stroking faster for me."

I felt incensed. Her voice sounded so authoritative.

"And while you jack off, I want you to think about me. Think about what's under my clothes."

She stared into my eyes. I could see it. The curve of her naked ass. Her pussy, no doubt wet and inviting. Her large breasts, bouncing as I thrust in and out of her.

I grunted. The pleasure was building up.

"Can I have permission, to cum?"

"Cum for me!" she said. With a few strokes, my penis erupted, cum spraying across my body. A droplet landed on her face.

She wiped it with a tissue.

"Good job, Mark." she leaned in and kissed me on the cheek. "Now we're going to measure your refractory period. As soon as you get hard, we'll continue with a different type of pleasure."

She smiled. It didn't take long for my dick to stand up again.