The lecture theatre was about half full, occupied by 30 students, randomly scattered among the steeply raked seats, males and females in equal number. They were as earnest as anyone could wish 20 year old students to be: Weighed down with textbooks and notepads, pens at the ready, they sat quietly waiting for the lecture to start.

At 10:30 precisely, the doctor took the floor.

"Good morning students, and welcome to our live presentation 'Exploring the human body.'"

"My name is Dr Mike Britten, and with me today are Nurse Jenny and our volunteer model Deena. As you can see Deena is wearing offender security chains as she was recently convicted of drink-driving. That's your first lesson of the day: Don't drink and drive, otherwise you might become our next assistant!"

Having elicited a first nervous laugh from the audience, he felt he had captured their attention. Dr Britten wasn't much of a comedian but knew the importance of a few well-rehearsed wise-cracks to get the students on his side.

"Today we will demonstrate some of the most modern equipment for safely probing the human digestive system. You will be able to follow procedures in fine detail thanks to the video screen. A full video recording of the lecture will be ready for download tomorrow. OK, we have a lot to cover, so let's get on with the show! Deena, please take up your position."

Deena stepped tentatively onto the low platform and assumed her hands and knees position to the maximum extent her chains would allow. Nurse Jenny started fiddling with the shoulder straps of Deena's dress. Deena's mouth gaped open in shock as the top of the dress fell loosely to the floor, giving the students a clear sideways view of her dangling breasts. Nurse Jenny then pulled on the sides of the dress. Accompanied by the ripping sound of Velcro and with a theatrical flourish Jenny pulled the dress clear of their model, leaving Deena naked but for her collar and chains. A shiver of excitement went up from the students as they re-settled themselves in their seats, in anticipation of what was to come.

Deena soon learned it was the equipment that was the star of the show, hers was just the supporting role.

"The first piece of equipment that we'll use is the very latest Sonitsu Auto-Intubator (TM). This will provide a safe corridor into Deena's stomach so that we can use endoscopes without causing the patient any discomfort."

Deena's face was level with the doctor's knees as he stood and placed a finger under her chin, indicating she should raise her head a little. "Don't worry Deena, it won't hurt. It will just tickle the back of your throat as it goes down." The Doctor's tie-clip microphone relayed even his quietest words to the audience.

He pushed the tube into her mouth. It almost felt alive, like a thin snake. Without any further intervention from the doctor the intubator steered and wriggled itself down her throat. It took just a few seconds. Deena was left with a two inch piece of tubing protruding from her lips.

Dr Britten used his trusty two foot long white cane to point at the video screen showing a diagram of the throat. He addressed the audience: "Let me explain what just happened: When I placed the intubator in Deena's mouth, it sprayed her throat with a local anaesthetic. Once it detected her epiglottis and registered that the anaesthetic has taken effect, it made its move and slithered painlessly down her throat. The end is now in the middle of her stomach. This device is far safer than the manual technique, and great reduces the need for anaesthetic and the possibility of human error."

Nurse Jenny handed the doctor some thin strips of surgical tape. "Next we'll need to tape the tube in place, which will be more comfortable for Deena." He carefully placed several strips of the white surgical tape over Deena's lips while also wrapping the tube with each strip. Deena could see a close-up of her face on the video screen. The strips of tape completely covered and sealed her mouth like a gag, with just the cigarette-like end of the intubator tube protruding.

"This intubator has a very special feature." the doctor continued "Although it appeared quite flexible when first introduced, over the next ten minutes it will become increasingly straight and rigid, obliging the patient to alter the angle of their neck to accommodate it. Thus it is easy to insert further probes into the patient's stomach."

He turned his attention briefly to his intubated patient. "Does that feel okay, Deena?" She nodded with great difficulty, alarmed that the flexible rod was already dictating her posture. It also governed what she could see, and left her no alternative but to look straight at the video screen.

Deena saw her helpless taped-up face on the big screen just a few feet away. The students laughed when they saw her face red with embarrassment at being forced to confront her own image, a naked girl chained on all-fours, her shiny-collared neck bent back so her mouth was aligned with her esophagus.

"Now we will fit Deena with a catheter. This is a tube that goes in her urethra and right into her bladder. Look at the screen now and you will see Deena's vulva. Nurse Jenny is holding open her labia so you can see the urethra. At the top of the screen you'll see her prepuce and the tip of the clitoris which we'll be looking at in more detail this afternoon. Nurse Jenny is now inserting the catheter. You can see by Deena's expression that it hurt a little as it was inserted. Now the tube is in the bladder and you can see her urine draining into the bag that Jenny is taping to Deena's thigh.

"Later this morning we will conduct a visual examination of the large intestine with an anal endoscope. Of course it's usually rather messy down there so we first need to give Deena an enema to clear out her system."

The screen's picture changed to show a close-up of Deena's neat puckered ass-hole and Nurse Jenny's latex gloved hand rubbing a lubricant around the entrance. When the nurse's finger slipped in her hole Deena squirmed instinctively and lowered her hips to the floor. The video picture now showed an out-of-focus picture of the back of Deena's head, much to the doctors annoyance.

He delivered a sharp blow of cane onto her thigh. "Keep still, Deena! Get back in position please!" he commanded her with some irritation. The microphone relayed his comments to the audience, causing some students to laugh nervously, while others were briefly shocked by his severity.

Deena continued to watch the screen, unable to avert her eyes from it because of the rigid tube down her throat. Tears started to obscure her eyesight as she witnessed a plastic tube was being pushed slowly up her anus. She began lamenting that she hadn't just accepted the prison sentence. The Doctor quietly wiped her eyes with a tissue while the students were engrossed in the action at the other end of Deena's body.

A five foot high metal stand held the enema solution in a clear bag. A tube descended from the bottom of the bag and gently turned into Deena's anus several feet below. "Nurse Jenny will now start to release the enema solution into Deena. This will fill up Deena's colon with a balanced cleansing solution." the doctor explained.

Jenny opened a valve and Deena could feel the wet warmth slowly invading her rectum. The screen briefly cut to showed Deena's eyes widened with panic.

After two-thirds of the bag had been administered, Nurse Jenny started to massage Deena's lower back around her belly chain, and encouraged a gentle hip movement. "Good girl, Deena, just a little more to go, sweetie", she whispered kindly. The liquid continued to fill past a point that Deena thought impossible, she worried that she might simply burst open.

Dr Britten continued his commentary: "That's all two litres now in Deena's colon. Nurse Jenny will seal the anal plug for ten minutes to let it get to work, while I explain a little more about the esophagus and stomach. Take a look at this diagram...." He took the students through a series of high quality images on the video screen.

Deena was becoming more and more agitated by the soapy liquid bulging within her and started to shift around a little, but sensed how utterly at their mercy she had become. Her eyes met the doctor's briefly as he stood in front of the video screen. Whining and whimpering pitifully from behind her taped mouth, her blue eyes pleaded with him. Her interruption of the doctor's lecture was met with another stinging hit on her thigh with the white cane.

"Quiet please, Deena, the students are trying to concentrate!" he said, annoyed by yet another interruption. The lecture hall erupted in chuckling, all at Deena's expense.

Nurse Jenny had placed a large bowl on the stage between Deena's open knees. "Ok Deena honey, we're going to remove the plug. Sit back on the bowl and let it all out."

That's exactly what she did. It was easy, and yet it was the most embarrassing moment of her life...so far.

The sight, sounds and smell of Deena's evacuations met with a predictably juvenile reaction from the students.

"Oh my god, that's so gross!" one of the female students called out.

"Yeah, and what an awful smell!" another said, her nose screwed up in disgust. What sympathy the students initially had for Deena appeared to have evaporated.

Surprisingly the Doctor came to Deena's defence and admonished the students. "That's quite enough of that kind of talk. I'd rather smell Deena's faeces than yours after you've been to the curry house!"

Nikki, the classroom assistant, had the onerous job of taking the bowl away while Nurse Jenny wiped up, ready to repeat the process. She began hooking up the next enema while the doctor continued with his slide show.

By the time Deena had accommodated her second enema it was time for a coffee break.

"OK students we'll take a ten minute break and when we return we can take a look up Deena's nice clean rectum and colon", the doctor announced. The lecture hall soon emptied amid noisy conversation. Deena was surprised to notice that Jenny and Mike had also walked out in search of coffee and a cigarette.

Deena was alone in the empty lecture theatre, but her colleagues had kindly left an image on the screen for her to look at. It was the camera view from the back of the theatre - a sideways-on shot of a naked woman, kneeling in a doggie position, a bulge in her belly, the enema device at one end, her face held rigidly forward looking like as if she had a cigarette in her mouth. 'Chained like an animal', Deena thought angrily, then realised that she'd never seen an animal quite so cruelly treated. 'I'm not going to cry. I'm not going to cry. I'm a brave girl. I'm not going to cry." she repeated like a mantra, as she felt a cramping pain in her belly.

After perhaps five long minutes of misery Deena noticed someone with red hair walking towards her. It was Nikki.

"Hi Deena, how are you doing?", she ruffled Deena's hair playfully. "Aw, don't cry Deena, here, let me wipe your eyes with a tissue. You don't want people to see you're crying. I think you're doing great for a first day." She sat down beside Deena and took a slurp of coffee. "If it's any consolation, you've got some fans amongst the students, particularly a few of the lads. I just overheard some of them chatting about how sexy you looked and the girls thought you very brave so don't disappoint them now.... Only another hour to go, then I'm going to take you guys for lunch. You must be starving."

The intubator tube was now so rigid within her that Deena could only nod by dipping her whole body forward.

Mike and Jenny returned to the lecture stage with their plastic cups of coffee. "How are you feeling, Deena?" Jenny asked sympathetically, while stroking the girl's forehead.

Deena made a strange angry sound and glared her angry eyes at the nurse, as if to say "How the hell do you think I feel?" She hated Jenny at that moment, yet somehow sensed the nurse's kindness. How is it, she thought, that Nurse Jenny was her tormentor and her saviour and friend at the same time?

"While Nikki's here, let's have this enema out of you and get cleaned up before the students get back. You should be clean enough for the demonstration." Nurse Jenny suggested. "Are you ready to go? Deena? Nikki?"

Ten minutes later the lecture recommenced. Deena was feeling better, not to mention cleaner, although becoming tired of the rigid position of her body and head.

The Doctor held out his next piece of equipment. "This is a gastro-endoscope, one of Sonitsu's finest products. Using its auto sensors it will slip easily down Deena's intubator tube. I just insert the first part in the tube like so...and down it goes. Quite painless, of course." A thin wire trailed from the front of Deena's mouth to a control panel.

"From this control panel I can steer the endoscope within Deena's stomach. The lighting on this model is fantastic. As you can see the stomach is almost empty but for a little chyme. This little girl will be feeling quite hungry soon!"

Even Deena was fascinated by images from within her stomach. She was pleased to notice the doctor's cane was only being used to point to things on the screen and not to strike her. She wanted to keep it that way.

"This very special endoscope also has the ability to take a sample for a biopsy." Dr Britten explained enthusiastically. "Watch the screen closely and you will see a tiny arm extend and cut a small piece out of Deena's stomach lining. All I do is instruct the device with the control panel and it makes the cut by itself."

Deena expected to feel a nipping pain as she witnessed the action on the screen but she felt nothing. The doctor explained that there were no nerve endings in the stomach, so this procedure was totally painless. That part of the demonstration ended after they took a quick look into Deena's small intestine.

-oOo-

The final demonstration of the morning session was the anal-endoscope, or what was called an 'endosnake' due to its method of self propulsion within the body. The screen showed once again the nurse's latex gloved fingers gently lubricating Deena's anal opening. This time Deena held perfectly still as Jenny's finger tested the anal sphincter. Dr Britten held up the next device to the audience.

"This beautiful endosnake is the big brother of the one we just used in Deena's stomach. It contains the most advanced auto-sensing motion motors in the world." The screen showed Mike holding what looked like a dead metallic snake about four feet long and half an inch wide.

It was one thing to have soapy water poured into your anus, but a metal snake with a mind of its own! Deena closed her eyes tightly to avoid staring at the frightening image on the screen. She just couldn't help wimpering and trembling as she awaited its invasion. Once again she was struck sharply on the thigh by the doctor's cane. At least he didn't feel it necessary to comment this time. The humiliating public chastisements were somehow worse than the actual swipes of the cane!

At first Deena thought that Jenny had pushed her finger inside her again, but as the 'finger' kept pushing forward she realised the endosnake had its 'head' in her rectum. It wasn't cold as she'd expected and moved gently but inexorably forward within her.

The Doctor gave a commentary: "If you look at the screen now you'll see the endosnake's progress. Notice the change of surface as it enters the sigmoid colon, so-called because of the 'S' shape. This endosnake steers through these bends with no discomfort for the patient. Now we are going through the descending colon. Beautiful pictures aren't they?" He paused for a moment to dwell on the wonders of the human body.

Deena opened her eyes and was increasingly fascinated by the metal snake's journey through her large intestine. It actually felt kind of nice moving inside her, Deena reluctantly admitted.

"Next we have the transverse colon.... we're right by Deena's belly button here ..... now we turn into the descending colon on the right hand side of her belly. Isn't that fantastic?... We finish in the cecum, which is the widest part of the intestine, and right there is Deena's appendix, looking very good. It may not look like much to you students, but I can assure you these pictures show Deena is the picture of good health. Proving that our model is beautiful inside as well as outside!" Deena still hated the Doctor but couldn't help but be flattered by his words.

The endosnake slowly wriggled its way back out of Deena, and she began to feel very nice indeed - her body pulsing with pleasure, better even than when the snake was going in! 'This damn thing is turning me on!' Deena thought, desperately trying to stay quiet to avoid another swipe of the Doctor's cane.

The doctor continued: "Although Deena is hiding it well, the endosnake has been designed to give a pleasant relaxing experience to the patient. It's a known fact that happy responsive patients heal quicker and better. The patient of today can look forward to their treatments without fear and worry. No longer do sick people have to endure painful procedures that merely compound their suffering. The endosnake is just one of many devices designed to make people feel good about their next visit to hospital.

Dr Britten wrapped up the lecture with a short question and answer session and a summary of the morning's demonstrations. Jenny was quietly packing away the endoscopes, while Deena remained in position, still with the intubation tube in place.

The Doctor addressed the students with some parting words: "We hope to see you all this afternoon for the 'Physiology of Sexual Response' where once again Deena will be our model."

The lecture finished to appreciative applause which rapidly faded at the students emptied the hall and ran off to beat the dining hall rush.

(Thank you to the readers who wrote encouraging me to continue writing this story.)