I was looking in the wanted section of our school's newspaper when I came across an ad for a paying medical study that paid cash. In calling the number in the ad, they told me to come into the clinic and I would have to fill out a couple of different forms. After that the study would take about an hour, but then I would get paid right after. Nurse Cindy told me that they didn't have any kind of a wait and that I could come right over. The clinic was just across the school's campus from the dorms, so it only took me about 10 minutes to get there. Sure enough there were only a couple of people in there, and when I was done with the paperwork she could be back to an exam room. I sat on the table waiting for the doctor to come in. A fairly young, male, doctor turned the corner, walked up and introduced himself as Dr. James. He told me that the study would be pretty painless, but that first he had to take my vital signs. We did all the basics, blood pressure, heart analysis, and he looked into my throat. The trial was on electrotherapy, and so I figured that it would be pretty interesting to try out. To get started, Dr. James asked me to remove my pants and underwear as well before taking a seat on the exam table. Seating down on the edge of the table, Dr. James started to feel my dick all over with a pair of gloves on. After he was done he said he was going to hook up a machine. He placed my balls and cock through this rubber ring that was hooked up to some wires. Turning the machine on low I couldn't really feel anything, but I heard the machine beeping. After a moment the beeping sound increased more rapidly, and then I got this slight tingling feeling all over my package. I let Dr. James know that I could feel it, and he asked me if it felt good. This study was all about my opinion, and so I told him that I really didn't care for it so far. I could feel the zaps my cock was receiving, but not much was happening. Dr. James however turning it up really high, and then examine my dick with his hands. Changing the pattern of zaps, the machine continued, and all I had to do was sit there. Finally, the doctor reached a point that I couldn't take and he turned the machine back down. My cock was getting harder by the second now, with the machine causing blood to rush into my cock. As my cock began to stand up, Dr. James started to give me head in hopes that it would get fully erect. My cock was a rock hard monster, and the doc was great at getting most of my shaft in his mouth. I couldn't help, but moan once in a while from what he was doing. After a couple of minutes, he didn't want my hard on to go to waste. Turning behind him he grabbed some lube off the counter, and applied it to my dick. Stroking me off really fast with his hand, we were both concentrating on what we were doing. I started to have an orgasm after what seemed like hours, and my body began to shake a little bit. I came all over Dr. James's hand, and both of us were out of breath. Dr. James said that the trial was a success and told me to come back in anytime. He then handed me a towel, so that I could start to clean up. It took me few minutes to let my dick and balls go down in size so that we could slip that rubber ring off of my dick. It was a very interesting study, and I do have to say that was the easiest job that I found to make some extra money.