When I had an office to myself and an admin, I’d frequently work late. After she would leave for the day, I go into my office, close the door and blinds, and frequently play doctor with myself. I’d undress down to my underpants and sit on top of my cleared desk. There I would put something cold on different parts of my upper body, mimicking a cold stethoscope and listen to my heart and lungs. I’d lay back and “allow the doctor” to lower my underpants for a brief genital exam, then pull them back up. At that point “the doctor” would have me get off the exam table and remove my underpants. I then had an old toothbrush, which “the nurse” would lubricate with lotion, and have me lay face down on the “exam table”. I’d be required to open my legs and receive the handle of the toothbrush in my rectum. From there “the doctor” would have me rollover onto my back for some nipple sensitivity testing. This included a retractable highlighter whose opening at the tip was large enough to place on my nipple. I had two such highlighters. “The doctor” would place the tip of these highlighters over my nipples, and depress the opposite end, forcing the highlight up and into my nipples, depressing them inward with mild discomfort. I’d do this a couple of times to experience the discomfort, and notice the reaction of my nervous system to the stimuli. It was always arousing and my penis was erect and dripping. I would often would stop to enjoy how humiliating it was to be nude and playing with myself in my office. By then, “the doctor” would say it was time to draw a semen sample and he would have me masturbate to ejaculation into a laboratory cup and send it off to the lab. I’d be allowed to remove the toothbrush from inside of me, wipe up, dress and go home.
Source: (27) masturbating at work secretly – Page 2 – Onania Masturbator Forum