She plays innocent

"Wow," She giggles. "Relax. This is just a massage. Not a date."

She gives your head a nudge to put it back on the table. "Now close your eyes and enjoy. I'll give your shoulders the release they need and then you give me what I need. Some feedback for my exam."

Her words calmed you down. She said it. Just an innocent massage. When she said "give me what I need" she was not talking about your dick. Was she? She made a little pause there. Did she tell you what she actually wants or what your rational brain needed for an excuse. You cannot keep your mind from wondering further what she could need. What kind of sex does your friend prefer?

Fucking her brains out with rough thrusts from behind? No, she is a strong woman with no submissive streak, isn't she?

Sensual tantric massages? That would fit the new job she is training for.

Dominating her partner as the strong girl she is and riding on top? That seems to fit her personality.

Maybe even harder fetish stuff? BDSM? That doesn't seem too far fetched to you now. Would you submit to her as a sex ****?

Your erection is grown a lot by this theater in your mind. Your position becomes increasingly painful now and yanks you out of your dreams. Your shoulder muscles also hurt a little from her treatment.

"I don't think I got that tension relieved yet." She does not sound satisfied with her work so far. "I need to work on you from a different angle. I'll need you to turn around while I get some more oil." She leaves the room before you can react.

You sit up and look down to your cock. Could you hide that erection under the towel if you lie on your back? Maybe you should end this here even if your friend would not get all the practice.