Kacey was in a bit of trouble.

It had been over a week since Shar had left town, flying back to her former home on the opposite coast to share the news of their engagement with her family. Kacey would have gone with her fiance had it not been finals week and had their future together not been riding on her passing grades. Both her mothers agreed: the wedding would not take place until after Kacey graduated. After a tearful goodbye at the airport, the young hybrid herm buckled down to study and put all her focus on passing that grueling week of testing. It was rough, especially given her post-graduation prospects at OmniMed, but the thought of Shar waiting for her when it was all said and done kept her going. Right up until the end, she kept telling herself that her canine companion would be waiting with open arms once the last test was done.
But when all was said and done, Shar hadn't come back yet.
The two kept in constant contact all week and a coastal storm had caused all flights out to be grounded until conditions were better. All Kacey's hopes of their reunion was washed away in those storms a whole country away. She was being overdramatic, she knew. Shar would be coming back a little later than intended... but the week of exhausting study periods and testing left Kacey drained and depressed. It certainly didn't help her parents had been away the whole week and only her Auntie Mabel had come by each night to cook dinner and help keep the house tidy. Even her trio of friends had been off on their own family vacation with her uncles, Rau and Caine. Kacey would have gone nuts by herself had it not been for a fortunate delivery one morning after finals were done.
It came by express, a special custom set she and Shar had had made almost a month ago at the OmniMed research labs. It was a bit of an employee-exclusive but Beverly had made an expection for her eager intern and produced a pair of sex toys: an onahole for Shar and a dildo for Kacey. But not just any dildo and onahole, these were made to specially replicate their partner's bodies. Kacey had giggled at the onahole designed to look and feel like her bunny cunny, marveling at the life-like resemblance... but her true focus was on the dildo shaped just like Shar's canine cock. It looked the part at first glance: a thick black shaft with the bulbous knot right at the bottom. A suction cup base was also molded for ease of use and Kacey wasted no time racing to her bedroom with the pair of toys.
The onahole forgotten, Kacey dropped to her knees on the floor, her pink member erect and her thighs already damp. She was breathing hard as she kissed the tapered tip and slipped the toy inch by inch into her muzzle. She closed her eyes, pretending she was bobbing her head on Shar's real member, letting the thick knot bump against her lips as she got the toy well and truly slick. She was too horny now, a week all pent up and alone now coming out in force, panting and gasping with need as she lay back on the floor, legs wide and guiding the toy towards her neglected pussy. She gasped when the tip touched her but desire took full control and she pushed the toy into herself, all the way to the knot. She gasped, back arched and tongue lolling out. A week without penetration or any masturbation... how did she make it this long without?
"Hah! Hah... hah!" she panted and moaned, crying out in the empty house as she worked the toy in and out of herself. That first thrust had broken the dams and brought the first orgasm, spurting all over her own breasts even as she kept going and going and going. She cried out Shar's name, cried out for more, cried out her love for the canine.
"Hah! F-Fuck me harder! Oh, Shar! <3"
She wanted it harder but her arms could only do so much. In her horny desperation, Kacey switched tactics and pulled the toy from herself. With more effor than she intended, she stuck the toy to the floor by the suction cup base and climbed on top. Panting like she was in heat, she lowered herself down and began moaning even louder. Kacey worked her hips every way she knew how, riding the faux member in all manner of ways and orgasming over and over. After what felt like hours, Kacey looked down at herself, seeing the multiple spurts she had shot all over the floor before her but not wanting to stop.
She wanted more.
She wanted the knot.
Now her moans took a differnt cadance, one that was a bit more forceful, more lusty and determined. She dropped her hips harder and harder onto that toy, feeling the knot slam against her clit, further fueling her need. She loved being knotted by Shar, loved it so much and missed it... she needed to feel it again, to feel the knot filling her up. She was pulling completely off the toy now, over and over, dropping her hips higher and higher until finally she shifted just enough that she gave one last, might drop of her hips, [putting all her miniscule weight into the effort...
Pop!
"Aaaaahhhh! <3 <3 <3 <3" Kacey wasn't sure when she last came that hard.
When she woke seconds later, she was on her side, panting heavily with her limbs feeling like jelly. Her nethers felt a little sore but they felt so nice and full... and that was when realization hit her. Her arms were weak after the marathon masturbation but her paws managed to find their way between her thighs. Sure enough, the thick silicone knot was sitting nicely plugged into her pussy.
And she couldn't get it out.
Panic and embaressment soon began to take hold. She was so horny and pent up, she never realized the consequences of knotting herself with the toy. Worse yet, her attempts to try and remove it had only stimulated her even further and cranking her libido back up in record time. The toy perfectly filled her up and any attempt to disturb it stimulated each area it touched mercilessly, making it impossible for Kacey to remove it herself.
She would need help... but from who?
Her mothers were out of town and so were her friends, Auntie Mabel wouldn't be over for many hours yet and even then it wasn't a guarentee any of them could truly help her remove the toy from her over-stimulated pussy. But there was one individual who could help, one with proper anatomical knowledge and could be trusted to be discreet... but would Kacey be able to make the trip when every step felt like it would bring her to orgasm?
She had to try.
Obtaining and using her cell was harder than usual in her current situation, what with every shift of her abdominal muscles causing that toy to rub somewhere deep inside. It was a bit harder to work up the courage to call the person she knew could help but she worked her digits all the same and braced herself for the call.
"OmniMed Science, Research and Medicine, this is Beverly," the calm and always warm voice of Kacey's employer gushed from the other line. "Hello?"
"H-Hi, uh... unh... i-it's Kacey..."
"Kacey? Oh, are you calling about your summer internship?"
Kacey felt her cheeks flush hotly and she bit down on her bottom lip to keep from crying out as she rallied herself to respond. "-No, I have a... mmh! I-I have... a p-p-problem!"
"A problem? Oh! Is it something quite personal? I'm a doctor, after all, you can tell me-"
"It's stuck!" Kacey wailed into the phone.
"Stuck?" Beverly repeated and only a heartbeat later she gave a surprised sound of realization. "Oh, my. Alright, I will reserve an examination room, can you make it here yourself?"
"Uh-uh... I-I can't move wi-without... c-cumming... " It was embaressing to admit over the phone but, as Beverly herself said, this was a doctor she was speaking to. Luckily, Beverly was more than understanding.
"I'll have a private shuttle fetch you. Try to dress if you can so no one will notice and I'll take care of the rest."
True to her word, the shuttle arrived minutes later, so small and inconspiciuous that she might have mistaked it for any other car had the driver not been a nurse wearing the uniform with the OmniMed logo on her breast. She was small, an adult female mouse who helped Kacey from her front door to the back of the shuttle before driving off at a quick yet modest speed. It felt like hours in the back of the shuttle, whimpering and blushing as every bump and turn jostled the dildo inside her. Kacey could feel her love honey soaking the seat, covering her muzzle tightly with her hands to cover her muffled cries as she climaxed again and again.
Finally, blissfully, they arrived at the OmniMed building where Beverly herself was waiting. She was dressed all business today in ehr usual blouse and pencil skirt, this time with her white labcoat as well. Another nurse was waiting beside her with a wheelchair out and ready but this nurse was different somehow; he was feminine but must have been a boi, a rather cute colt with a sandy blonde mane done up in a braid. Still, he wore the true uniform and was with Beverly so Kacey didn't bother thinking too much on him. She had more pressing concerns after all.
"Deep breaths, dearheart," Beverly soothed as she scooped Kacey from the backseat and into the wheelchair. "Sasha, we're taking her to exam room 4. Do try not to jostle her, the poor dear has endured enough already."
"Yes, Mo-.... yes, ma'am," the colt nurse chirped at once as they ferried Kacey into the medical pavilion.
Kacey had begun to flitter in and out of conciousness as the wheelchair moved and turned again and again. The orgasms were so frequent and had drained her so much that she wasn't even aware of when she was in the wheelchair and when she was finally lying still. Slowly, the world came back to her and she heard a relieved sigh come fromthe nurse boi somewhere in the exam room. Kacey wasn't in the wheelchair anymore or even on a normal exam table. She was nude and her legs were up in stirrups. A faint ache in her arm made her glance over to see the IV she was hooked up to and Beverly beaming down at her from the half-empty drip bag.
"Welcome back, kacey," she said softly and leaned down to kissd the hybrid's temple. "This is just to rehydrate, you were dangerously close to dehydration and no wonder." She paused, too mature to blush but Kacey could see the surprise in her expression. "Were you a bit impatient to take the knot? I assume it's the model toy we had made for you given how it's lodged... but you must remember to be patient and pace yourself with this toy."
Kacey blushed deeply and looked away for a moment before speaking. "I-I just... Shar's flight was delayed and... and I really miss her and... we never had this problem before..."
Beverly tittered. "Well, that's understandable. The knot naturally deflates over time and it's easier to pace youself when you have a partner working said knot. But this toy isn't natural, solid silicone doesn't ever deflate so you need to adjust yourself little by little. A little self-foreplay, so to speak. Some might say your fortunate this happened to your pussy but there are some who would argue the tailhole would feel better-"
"C-Can you get it out?" Kacey interruped, pleading to the bovine doctor. It was so embaressing but she needed her new favorite toy out of her so she could at least move without spurting and soaking her panties. Beverly tittered again and stroked the hybrid's monochrome hair.
"I'm a doctor, dearheart, this isn't the first time someone got a little overzealous with their toys." Her smile faltered a little. "It is going to be a little tricky... see, just as you'd need to stretch yourself little by little to take the knot, that's the same way I'll need to remove it. That's the other reason to keep you hydrated: you'll cum, a lot. That's also why you've been strapped down so you won't hurt yourself pulling on the IV. <3"
Kacey tried to move her arms then, realizing she was indeed strapped down and immobilized in the stirrups. A brief flutter of panic hit her before Beverly soothed her with a little embrace, resting Kacey's cheek against her ample bosom. Little by little she calmed down, remembering this was someone she could trust in the matter... even if it meant being tied down and forced to orgasm countless more times.
"There's one more measure we need to take as well. Sasha," beverly called to the nurse on the other side of the room. Like an obediant pet, he was at her side, bearing in his slender hands a red ball gag. "We do have soundproofed suites for patients experiecing intense heat but this exam room is not one of them. As such, we'll need to keep squealing to a minimum."
Kacey felt her heart and libido start to race. She hadn't experimented too much with gags yet but it had occured to her... but she'd been too shy to suggest it to Shar. This would be a first for her, being gagged to purposfully keep her quiet. It was oddly exciting and she couldn't fully grasp why just yet. Still, she gave a bashful little nod and said, "O-Okay. <3"
Beverly tittered. "Oh? Feeling a bit excited, are we? <3" She leaned in with the gag in hand, waving Sasha away as their faces moved closer. "Well, don't keep me waiting, dearie. Say 'aah'... <3"
Gagged and restrained, the proceedure was set to begin. Beverly had removed her clothing and labcoat, donned a mask and gloves and sat down with clear access between kacey's thighs. Pulling down her mask for a brief moment, she kissed both of the hybri's little orbs before pulling the mask back in place. Now was the tricky part as she gently took hold of the suction cup base of the toy and began to shift it. The reaction was immediate, Kacey crying out into her gag and struggling in vain against the straps. Beverly couldn't stop now, the love juices were already flowing again and that toy needed to come out.
"Sorry about this, dearie," she whispered and began twisting the toy in a full, slow circle, turning it inside of Kacey and driving the poor teen crazy. Beverly was glad she had stripped as the first of many spurt splashed her, Kacey's pink member firing off rapidly. It continued for what felt like ages to poor Kacey, reduced to a whimpering, squealing mess as she climaxed again and again and again as Beverly slowly and carefully worked the toy. Finally, the knot was halfway out and with one final full rotation, it popped free and let loose perhapos the strongest orgasm that day. Kacey arched her back as much as she could in the table and squealed so long it was a wonder the ball gag had kept her as muffled as it did. A torrent of her pent-up love juices gushed from between the girl's legs, soaking Beverly's lap as it all came rushing out at once. Leaning back to let Kacey finish her mighty, freeing orgasm, Beverly sighed and set the soaking wet dildo in Sasha's own gloved hands.
"Clean it up for her, sweetie," she instructed the colt. "It's quite precious to her so we must treat it with due respect."
"Um, Mommy?" Sasha whispered and motioned to the exam table where kacey was still strapped down. Soon Beverly could understand why, forgetting how Sasha broke their rule about titles in public.
Kacey was still aroused. Too aroused, her cock was still twitching and leaking and she was now writing in the stirrups, moving her hips like she wanted to ride something or someone.
"Oh, dear..." Beverly muttered and rushed to Kacey's side. "I've only heard of this happening once or twice, ever. I never expected it could be possible. Maybe because of her herm physiology or her bunny-side or..."
"What's wrong with her?" Sasha squeaked, clutching the slick dildo fearfully.
"Well, nothing really," Beverly admitted with a touch of blush on her cheeks. "Kacey is... well, she's in heat. The prolonged stimulation combined with any pent-up desires must have been enough to force her body to go into estrus."
Sasha seemed a bit more alarmed. "Wh-What'll we do?"
Beverly sighed but smiled as she reached down, rubbing Kacey's twitching member with one gloved hand and hearing the little moan of delight escape from around the gag. "We have the facilities to help her ride it out, but-"
Brrrring!
Before Beverly could finish speaking, the exam room's phone buzzed with an incoming call. Kacey whimpered in protest when the hand moved away from her cock as Beverly crossed the room to answer. Sasha was the first to notice the gleam of delight in the bovine's eyes as she listened to the call ad merely gave a quick 'Thanks' when it was over.
"Who was that?" Sasha asked softly.
Beverly smirked mischeviously. "There's a rather insistent labrador at the front desk asking about her fiance. She said she just landed an hour ago and came here, saying something about 'catching her scent'. This provides us with an excellent opportunity... <3"
Walking with that more dominant swing to her hips, Beverly leaned over the helpless Kacey, strapped down and gagged still. "Good news, dearie," she cooed and kissed the red rubber ball in the hybrid's muzzle. "Your beloved has returned and I have a special room just for you two. She can hold you down and show you just how to take that big... thick... knot. <3"
"MMMMMHHHMMM! <3 <3 <3 <3 <3" Kacey squealed, another orgasm exploding from her nethers just from excitement alone.
"I thought you'd like that. <3"

To Be Continued! <3