I didn't do as well as I had hoped on a recent anatomy exam, and that made me a little nervous about my grade in the class. After one of my classes I went up to my professor after everyone had left, and I asked him if there was anything I could do to get some extra credit to make up for the extra points that I missed on the exam. Professor Johnson said that I could go to the local school clinic and see Dr. Phingerphuck for a special experiment of anal stretching. If I took part in the experiment than he said he would give me enough extra credit to get my grade on the test up to an A. That was perfect, and just what I was after. I asked him how quick I could go down there to do the experiment, and Dr. Johnson told me that I could head down to the clinic and he would call ahead. The clinic was only a short walk across campus, so I knew it would only be like a 15 minute walk. When I arrived at the clinic the nurse behind the counter said that Dr. Johnson spoke with Dr. Phingerphuck. She motioned for me to go back to the exam room that she was pointing to, and I knocked on the door. Walking in the room the Doc was cleaning the exam table and he introduced himself. I explained that I was here to do an anal stretching experiment, so that I could earn some extra credit for my final grade. The Doc said that he would be happy to perform the experiment, but first he needed to take a quick look over me. I had to take off my shirt and the Doc listened to my heart and lungs first. Complimenting me on not smoking, he then looked into my eyes, took my blood pressure, and then got ready to check me for any hernias. I had to strip down to my underwear for that, and as Phingerphuck pressed down on my stomach he could see that I was a little cold and had the sweats from being nervous. Dr. Phingerphuck asked me to take off my underwear and getting back up on the exam table he had me spread my legs wide apart in these feet rests. After some adjusting on the table, the Doc explained that he would be start with doing some finger stretching first and then would work up to bigger and better things. The main important ingredient to getting started is lube, and to go heavy with it. He applied a lot to my asshole, and I just felt like it was dripping all over the table. Dr. Phingerphuck began to press his finger inside my hole, and it just slid in with no resistance. He then said that he would insert two fingers, and it was then that I could feel a little discomfort. With some deep-breathing and relaxing the two fingers wasn't a big deal either. The Doc even moved them around feeling my insides with his fingers and commenting on how hot it was. I couldn't help, but notice that with each passing second, the Doc seemed to be enjoying this experiment a lot more than me. Continuing on with the experiment we were now going to step up to three fingers. As Phingerphuck worked his way up to getting that third finger in my ass he slapped me on the ass a couple of times and that did the distracting that I needed. My ass just kind of swallowed the fingers right up. The Doc wasn't going to stop there he went to getting his pinky finger in as well. I couldn't help it, but be a little nervous with how much he was doing with my asshole. The whole time that the Doc was fingering my hole, I played with my dick to create a distraction for me to keep my mind on. Taking things to the next level, Phingerphuck grabbed some huge object off the table and he began to push it inside my ass. Then, he fucked me with it and I will admit that it did feel pretty good, and it had me turned on as I pumped my cock. At one point I almost was falling off the table, when the Doc had me trying to ride the toy myself. The last thing that he told me he wanted me to do was to take this plug and shove it up my ass and have me get off. When he picked the plug up and handled it in his hands I couldn't even look at, because my eyes told me it was HUGE! The Doc started slow and he pushed the plug in slow and steady. Once it was in all the way, he tapped on the end with his fingers as I stroked my dick. I gave the Doc a warning that I was getting close and I shot my load onto my stomach. Afterward, Dr. Phingerphuck said that he would tell Dr. Johnson to give me the extra credit I deserved. However, Phingerphuck offered me an option to get more credit if I come back for some kind of electro experiment. How could I turn that offer down?