Lucky Thirteen: A Masters' Class in Anal

By this point the usually uptight teacher's pet was bouncing Lewdly on the young doctor's hand, still desperately trying to reach the fingers above her face, balancing on her toes to reach them. This just gave Thirteen easier access.

Masters moaned deliriously when Thirteen finally pulled her left hand free and was then forced to grit her teeth as it joined the other in sodomising her butt hole. To Masters it felt like she was being torn apart as two sets of fingers began exploring her sphincter, prying her cheeks wide apart.

Thirteen saw tears begin to build up in the corners of the redhead's eyes and felt a pang of guilt. So she slowed her penetration once more and squeezed herself against the young redhead, cooing into her ear.

"Ohhh, it's okay. You're doing so well. Just remember to concentrate on the feelings I'm giving you and to hold still. Good girl, that's it, push back. Good girl!"

Masters blushed. She loved praise and still idolised the doctor that was working away at her. The redhead was always desperate to please figures of authority. And the pleasure soon outweighed the pain, confusing the already lost girl further. The pumping twisting sensation burned her loins with intense pleasure unlike anything she had felt before. So weird and wonderful. And then suddenly she was left feeling horribly empty as thirteen pulled away, her fingers coming free with a loud pop.

"okay I think I've loosened you up enough for you to experience a small colonoscopy." thirteen said as she crossed to the desk and open her bag once more. From within it she pulled her favourite strap on.

The brunnette then stepped behind the shaking girl once more before deftly unbuckling her own belt and pulling down her slacks. Then the young doctor strapped the large member around her own waist before bracing herself against Masters, teasing the head between the girl's legs.

Now The best way for you to learn here is if I stay still and you do the work, so you need to back onto my scope and press it into yourself. Think you can do that?"

Masters nodded and stepped backwards on shaky legs. Thirteen bent her knees to make up for their significant height difference.

Masters felt a hard object press between her cheeks and saw the colonoscope in her mind's eyes. She bent further forward before guiding the tip into her butthole. She cried out as the large member entered her behind gradually, the excessive lubrication of the gel making the job considerably easier.

Thirteen watched, wide eyed as Masters speared herself on the dildo, bracing herself against the board so that her base stayed rigid.

Masters hands swung around wildly, desperate to find enough purchase to continue but only finding open air. As a result she had no choice other than to grab at Dr. Hadley herself. This time it was Thirteen's turn to gasp as master's flailing hands found her own panty clad ass cheeks, nails digging into her firm behind, her fingers tangling in the red lace of her thong. As the anal invasion continued Masters even tightened her grip, unintentionally giving a wedgy to the superior doctor. Thirteen loved the sensation.

In this position Inch by inch the dildo penetrated the helpless girl, taking her anal virginity as her rosebud was forced wide open around the large shaft. Masters panted freely but eventually had all 12 inches of the dildo deep into her ass, the tip embedded in her lower colon.

Finally Masters registered her soft bottom slapping naked thighs behind her, but was incapable of reasoning, her focus entirely on the huge object that filled her rectum.

"Good girl!" said Thirteen, as patronizingly as ever "that's a nice stick." Thirteen began rotating her hips, swirling the dildo and the gel that covered it deep into the girl's bowels:

"Now you're obviously spent so just hang onto me any I'll do all the pumping for you. Just keep remembering that we're now right into your colon. Take deep breaths, that will loosen your abdomen."

Thirteen began slowly removing the dildo. As she did Master's butthole squelched delightfully. The redhead squirmed, bracing herself, without the colonoscope deep in her sphincter she felt strangely empty and the contents of her bowels twitched unsettling.

Then she groaned and slumped back against Dr.Hadley as the brunette thrusted hard back into her butthole raising her onto her toes, before pulling back once again causing her to mewl pathetically.

Soon Thirteen had a regular rhythm going, pushing harder and faster into the long gone Masters. For all her intelligence and paranoia the girl had lost all of her composure. Her head lolled from side to side and her big brown eyes started upwards; unfocused on the ceiling. Her soft pink mouth was wide open, forming a silent 'O' as she was penetrated repeatedly.

Whilst she stuffed the young Intern, thirteen's hands were free to roam the girl's heaving body, the mind that controlled it too wrapped up to notice the fondling.

For Thirteen this girl was just too adorable, all soft and warm. One hand played with Masters' belly button whilst the other fondled the redhead's glorious breasts, which bounced delightfully with each thrust. Soon both hardened as the brunette pinched each nipple, becoming points.

Master's was now unbearably hot, panting ferally whilst she shuddered like she was on a horse's saddle, not a fellow Doctor's dildo. Soon her pulse was racing and a stronger sensation spread from her loins, carrying her whole body.

"Dr-Dr. Hadley! I think I'm experiencing something new, my heart rate is increasingly exponentially whilst I'm feeling, ahhhh, pleasurable sensations."

Thirteen however, was just coming to a boil and wanted both of them to orgasm together, so when she had to speak convincingly:

"Those are bowel tremors, normal but not ideal! You need to fight those sensations, push them back down!"

Masters did her best, thinking of the diagram, now a little smudged before her, that depicted a woman's digestive tract.

Desperately she clenched her bowels, tensing her cheeks and abdomen. Dr. Hadley however just doubled her force, lifting the redhead clean off the floor now with each thrust. Master's teared up once more, drops mingling with the sweat on her face, now delirious with pleasure and fatigue:

"I-I, can't fight it anymore Dr. Hadley, It's too much!"

Thirteen groaned with effort, clenching her teeth before she came abruptly. Wildy she pitched forward, crushing Masters against the board as she orgasmed, hard. Throughout she never stopped thrusting, the redheads poor rectum pounded until it was effectively useless.

"Let go now!"

The young intern came on command, though to the hapless girl she had no idea of the pleasure's true nature. All of her body let go at once and she felt an immense sensation of release, her bowels rumbling as they were mercilessly squeezed.

Then she burst repeatedly, her pussy giving way and squirting the board in front of them, spattering Master's diagram.

The girls clung to each other, exhausted. Slowly they began to come down, sliding down the board a little as Thirteen came to a stop. Both were utterly exhausted.

Thirteen eventually recovered enough before slowly beginning to pull her dildo free of the redhead's butt, but abruptly stopped when Master's exclaimed:

"Please don't. I- I don't think I can handle you doing that right now. I-I, just need a sec."

Unbeknownst to Thirteen, the redhead's attempts to stop the 'rectal tremors' had an unintended side affect. Clenching her abdomen had cause Master's to let go off her lunch, and it was taking all of her energy just to stop herself from soiling her superior Doctor.

Thirteen, turned Masters' head, saw the beads of sweat on her forehead, the strain in those big dark eyes, the fear and simply guessed the rest.

"Ohhh, I see... Can you hold it till you get to a bathroom?"

Masters gritted her teeth, shaking her head as she replied:

"if I move I'll burst. Ohhhh, this is so embarrassing."

Thirteen stroked Masters' hair cooing softly, them remembering the other items he had in her bag.

"it's okay, just hold still while I pull out the colonoscope. I can help you."

Thirteen stepped back, her dildo squelching free with a pop. Masters groaned and twitched but kept her eyes of the blackboard. Thirteen inspected the girl's once tight rosebud and cheeks as she removed the phallus and quickly pulled up her tight slacks. The redhead's butt was now bruised and gaping. No wonder this girl was on the verge of soiling herself, anyone would be.

The brunette then crossed to her bag, replacing her dildo and retrieving a round, plastic white instrument that she brought back over to Masters. Then she knelt behind the redhead, praying the girl was still holding strong as she quickly lathered the object in her special gel before raising it into position.

Martha yelped as another foreign object plunged into her sphincter, going deep inside before lodging itself there. Now she couldn't relieve herself even if she wanted to, her rectum effectively corked. Dr.Hadley had inserted a butt plug.

Thirteen stood back and admired the results, the girl shaking but now attempting to move, testing the foreign object in her loins. When it didn't give the redhead sighed and then groaned. Any sharp movements were uncomfortably tight and for reasons that deeply disturbed her the redhead was now even more aroused than before, the extra gel messing with her head.

Thirteen nodded approvingly: "That will do it, but try not to move too fast or bend over far, that won't end well."

The brunette then helped tidy the young intern up, pulling up her adorable panties before covering them with the ruffled up skirt around Master's hips. Then thirteen passed the redhead her books from the desk before leading her to the door."

"well I hope that was informative, you now should have a pretty good idea of what a patient feels when their digestive tract is pumped."

Masters nodded feebly, dark eyes still wide and unfocused. The redhead did react however, gasoing when Thirteen continued:

"This actually presents another learning opportunity. I want you to keep that plug in for the rest of the day. That will give you an even better understanding!"

Masters gaped: "But, but! I have another lecture now. I can't stay like this all day!"

Thirteen gave the girl her most authorative stare: "Don't disobey the teacher Masters, I could still fail you. Just think of this as unofficial extra credit and I'll see you tomorrow."

Thirteen squeezed the girl's soft behind fondly before sending her away, grinning from ear to ear.

Masters walked away slowly, moving awkwardly. Her stance was noticeably wider than usual.

The teacher's pet wouldn't take another note all day, incapable of sitting still or focusing. Instead she would fidget and squirm on her sore butt, desperate to relieve herself and hornier than ever before.

Thirteen laughed as she locked her the lecture room's door, strutting away down the corridor. Very satisfied.

Masters would be getting a few more private lessons is week.