"Just a little further up this way, miss."  The attendant said cheerfully.

Becca followed closely behind her, glancing at the passengers stowing their luggage and taking their seats in cramped confinement. They looked uncomfortable packed so tightly together in those small seats, but they looked content in each other's company. 

'Crammed but content', she thought as she followed the attendant toward the back of the train, discreetly tracing a hand over her left butt cheek.  Maybe one day ‘crammed but content’ would come to describe the boy she’d been entrusted to protect with her butt. She considered asking Dr. Walker what the boy’s name was, but for some reason, she just couldn’t.  It was as if something inside of her deemed the knowledge dangerous and wanted to protect her from it.

Becca and the attendant crossed several train cars that all looked identical: the same small seats with the same kinds of passengers.  They all looked the same and soon she wasn’t observing the nuances in their movements, dress or disposition.  They were all the same to her now.  

She didn't look down on them though...of course not.  Even riding in coach wasn't something Becca could afford to do, and the luxurious train suite she was about to enjoy would have normally been well beyond her wildest dreams.  She did not forget that it was paid for entirely by R&R Labs, and she certainly appreciated it.  

"Alright; just a bit further until....ahh...here we are." The attendant said, pointing to the temporary placard that said "Miss Becca Young".  The attendant tore the paper cleanly off the door and pulled a light purple RFiD card from her back pocket.  

"Let's get you settled, shall we?" 

The door opened and Becca could not believe what she saw.  It was basically the size of one of the train cars she had been walking through, but instead of there being a bunch of people and seats, all that space was for her.  Well, truth be told, it was half a train car?the back cars being split into two luxury suites divided by a narrow hallway...but Becca had the whole half to herself.  It was stocked with furniture, a large desk and comfy chair for letter writing and business.  There were flowers, beautiful lights, rich wooden paneling, and a queen sized bed that seemed to just fit side-to-side.  There was even a bathroom!  And not one that she would have to share with a car full of train-goers...one to which only she had access.  The attendant set a key down on the table near the door.  

"Is it to your liking, Miss Young?"  

Becca turned and smiled, "Oh yes, it's beautiful."  

The attendant returned with a warm, proud smile.  "I'm glad.  Well, I will leave you to your room.  My name is Sasha, and if you need anything please do not hesitate to ring!"  She said, gesturing toward the phone next to the bed.

With that, the door shut behind Sasha, and Becca was alone. 

'Well...not completely alone?' she thought to herself.  

That was a realization she had earlier that day in the lab, and she realized that she would not truly be alone for a long time to come. Not with the tiny boy living between her butt cheeks following her everywhere she went.  She realized something else, in the time she had been following Sasha to the back of the train, she had done a fair amount of walking, and she had barely thought of the boy in her butt. 

Sure, as she thought about it now, she could feel his movements and she wondered if he ever got tired…

…but it was almost alarming how little stimulation or focus was required for her to completely forget about him in there.  

Her young, sharp female mind had tackled several logistic and social tasks in the past few minutes all while gravity and the genetic gift of a large booty teamed up in securing the little naked boy with barely any thought and absolutely zero effort.

But now it was just the two of them in here.  Now she could focus on him for a moment.  

It was strange...for some reason, knowing he was there made her feel safe.

 'Isn't that just silly?' she thought to herself.  'I'm keeping him safe with my butt like...literally in every way possible...with the softness and cushion of it…with its temperature...and somehow I'm the one that feels safe'. 

It wasn’t THAT strange of a thought, she supposed.  Sure, she was protecting him with her rear, but if it wasn’t for him, she wouldn’t be getting $350 every two weeks!

She set the overnight bag she’d brought down at the entrance and pulled out her phone, it was 8:07pm.  That meant the boy had been in her butt for about 2 hours now.

She wondered what he might be thinking right now, and she was tempted to take him out, but she remembered what Dr. Walker had said: no less than 3 hours away from her booty. Or had it been 5?...she couldn't remember exactly.  

Becca picked up her bag and put it on the bed.  

'Oh', she thought, looking at the green square on the pillow.  'it's a mint.'  

She felt even more luxurious as she opened it up and her teeth sank into the cracking chunk in what seemed to be a 5/95 split.  She held the remainder on her finger as she chewed the tasty chocolate, letting the mint coat her palate and tongue.  The remaining tiny piece adhered to her finger, shining a bit along the teeth marks. It was a very small piece, something a normal person like her would only slightly taste...'but it would be a perfect treat for the boy', she thought as she lightly patted her heavy, dense butt cheek. 

When she took him out, that is.  

It didn't seem fair...the both of them were participating in this experiment, and while she was getting flights and first-class train rides...he was tucked deep between a set of soft but firm, warm butt cheeks.  It sounded like it might get boring for him, but she had to tell herself that Dr. Walker was right.  He had signed the line just like she did.  But still, she saw it in her power to make his experience a little more enjoyable..it didn't take much effort, as she would be removing him from her crack anyway...why not give him a tiny morsel of chocolate?  Especially since she was going to be starting those strange vitamins...which meant he would be starting…

'ugh...one thing at a time', Becca thought. 

She pulled the manila folder she’d received from Dr. Walker out of her bag and left the rest on her bed, walking over toward the chair and desk. She scooted the chair out and slowly lowered her large rear into the cushioned seat. She knew he would be okay, but it just felt...disrespectful to sit as quickly and thoughtlessly as she normally would...like when you walk past a custodian mopping the floor:  you have no choice but to walk right through his work, but you tip toe, even though you know it makes no difference, but it makes it seem like you care.  

Becca wanted to let the boy in her butt know that she cared, as pointless as the gesture may have been otherwise.  

She gradually allowed her hefty rump to sink into the thickly-woven cushion and enjoyed the sensation of her weight leaving her feet, gradually centering fully on her wide, splayed ass.  With her flip flops slid off, the carpeted floor felt nice and rough against the soft soles of her bare feet.  Becca opened the manila envelope. 

The receptionist said that the generic vitamins she’d picked up on her way out of the lab were not an ideal long-term supplement because they lacked the custom-designed material to interact with her own body.  They were suitable for the short term though.  The receptionist had explained that since the vitamins were basic, they could be modified to develop a pleasant flavor when absorbed and passed through Becca’s body during digestion.  Basically, her perspiration would taste sweet, which made her feel a lot better about him living off of it. 

Unfortunately, the flavor modification tweak was not available in the specially prescribed variant that the subject would be purchasing monthly, so when she switched over, the pleasant taste would be gone.  At that point though, it was explained to Becca that he would have already gotten the point that consuming her perspiration is how he is expected to survive, and with no other options for sustenance, he will understand that he must continue to do so.  

Sure, it would be great if he enjoyed the flavor, but being healthy was far more important than taste.  It felt like a very ‘mom’ thing to say.  This really was part of it; she was taking care of him, so it was her responsibility to not only know what was best for him, but to be firm about enforcing it.  Dr. Walker had added that she was confident that the subject would develop a taste for the unflavored perspiration anyway, given enough time.  

Until then, however, he would have the generic.  

She set the rattling pill container on the edge of the desk and leafed through some of the documents.  The first was a notice with her signature.  The header read: 

GLOBECOM MANUFACTURERS: A Subsidiary of BexCorps  

Below a large body of technical jargon way beyond Becca's understanding was some italicized text, the only text that Laura said she had to worry about:  "I, the aforementioned, consent to regular monitoring by use of GPS positioning, accessible at any time by R&R Labs for official use only". She remembered this was one of several forms she had to sign today, and honestly a lot of them blurred together.

It was explained to Becca that the lab had recently contracted work with GlobeCom, a company mainly aimed toward the manufacturing of super-small semiconductor devices such as BJT and MOSFET transistors, had been bought out by a company called BexCorps, which Becca knew very little about.  It apparently was a big purchase, since GlobeCom themselves had recently acquired a popular, confidential GPS company, and were now expanding their operations.  They were contracted to manufacture nearly microscopic GPS tracking systems, but they were not informed why. Becca understood why, but only because it was explained to her.

There were too many situations where subjects, while away from their caretakers' rear ends, went missing or were otherwise injured.  GPS tracking allowed for recovery of these subjects, and sometimes they were even able to be retrieved prior to their expiration.  Once recovered, the living subjects were mostly fine, albeit some psychological scarring depending on what the Participant's negligence caused.  One thing was for sure though:  whether they were recovered and returned to their Participants, or kept due to injury or death...there was plenty to learn from the experiences."

"Ugh..."  Becca thought, rolling her eyes as she set the paper down.  She had an itch on the back of her upper thigh, right where the thigh meets the cheek, but the underwear was so insanely tight she couldn't even get to it.  She really wasn't a fan of it, to be honest, and now that she was ‘alone’, she could change into something more comfortable.  She stood up from the desk and pulled the blinds down so no passer-by could see into her luxurious room. 

Once the blinds were down, she unbuttoned her jeans and wiggled out.  Standing there in nothing but her shirt and tight underwear, she hooked her thumbs into the waistband.  It was one thing putting them on, but taking them off was quite simple.  She simply started yanking down side by side, alternating as she wiggled her hips rhythmically. The waistband stretched over her cheeks, getting tighter and tighter as they peaked over the mountainous flesh's peak...and then it was all downhill from there…quite literally.  Her pale white butt cheeks practically exploded with a celebratory jiggle out of the underwear and she couldn't help but giggle and sigh at the relief.  She looked into the mirror on the wall and saw deep imprint lines from the underwear tracing along her butt.  The cold air felt nice. She scratched at the persistent itch at the base of her ass cheek and got goosebumps. 

Once her big butt was fully out of the underwear, she immediately felt it.  The boy in her butt, just now feeling the heavily compressed butt cheeks relenting their strong inward pressure, must have seen this as a golden opportunity to take a mile out of an inch.  Becca actually gasped when she felt the struggling increase in her crack.  

"Oh my goodness.." she thought, her hands instinctively going down, one to each butt cheek.  

Without thinking, her fingertips sunk into the curvy, soft hemisphere of her cheeks along their outer edge and she pressed them together, sandwiching the subject firmly in her crack. She’d definitely overdone it, the inward pressure greatly exceeding the amount of force the underwear exacted on her bottom, but her cheeks were very soft so Becca was confident that he would be okay.  

She shimmied her hips, as the training underwear was still at her thighs, until the underwear started coming down and landed on the tops of her bare feet.  She stepped out of them, leaving them on the floor. 

Becca looked around for a moment and saw her bag on the bed.  She waddled over to it, still firmly holding her cheeks together as she quickly and expertly pulled a pair of blue polka dotted panties from the bag.  They were mesh/see-through, and she hardly ever wore them, but she decided to bring them because she thought it might help the boy in some way.  Maybe the transparent material would allow a little bit of light in there for him to see?  Or maybe the material would breathe a little bit better and help increase air circulation?  She stepped into them and hiked them up over her rump, and her clenched cheeks fit much easier into these than they did the other tight underwear.  Once they were up and over her ass, she felt she could finally unflex her ass cheeks.  

Becca could still feel him fighting her buttcrack, but she definitely wasn't worried about him parting her cheeks.  Still...it was at this moment she realized that the underwear definitely had a purpose, and much to the poor boy's dissatisfaction, that was most certainly not the last time she would be wearing them. 

She sighed in relief and then returned to the chair to review the documents.  The next one had the R&R Labs header she'd seen several times already, but this packet she only glanced at when Laura put it inside.  The first page asked for the stuff you’d expect: name, age, subject’s ID number…and it also briefly went over the minimum requirements for the experiment.  

It talked about how the minimum time she had to keep the boy in her butt, the Dynamic Daily Minimum, was 6 hours for the 1-month tier she’d selected, but Dr. Walker said that she could start out at the lowest threshold of just 3 hours.  Becca thought it best to fall somewhere between those numbers. 

The next page of the packet said "Activities to Monitor". 

These were activities that a woman might perform in her normal day-to-day life as well as some things to try solely because said woman was participating.  The idea was to engage in these activities and monitor the subject's response as well as the woman's own personal feelings about subjecting the boy to the experience.  Laura clarified that thinking about how something affects the subject is not something we as participants should get in the habit of, but the periodic monitoring is important for R&R Labs research and documentation. Becca started viewing the list and at the top was AEROBIC EXERCISES.  It recommended cardio, weightlifting, and even sauna/steam room visits.  That made sense to her.

The next two made her blush:  

SEXUAL INTERCOURSE/MASTURBATION  

She didn't really do those things very often…the second one not so much, and the first one even less.  The idea of masturbation, to her at least, was a very private thing...the idea of doing it in front of the boy was kind of embarrassing but then again what did she have to be embarrassed about?  It was completely natural for a girl her age to be doing that sort of thing.  Actual sex...while he's back there?  That might be a little too much for her.  She was glad to see that these were not hard requirements.  Instead, there seemed to be monetary rewards for taking part in some of these activities, so long as documentation on results were detailed.  SITTING.  She could certainly handle that one. SWIMMING. There was a note next to it that said "EXPERIMENTAL: CONTACT DR. WALKER PRIOR TO ATTEMPTING). 'Hmmm', she mused, 'I may have to do that...I do like swimming'. 

Next was the banking statement; she'd already seen that.  After that were about several dozen copies of a single set of pages adhered with a tiny paper clip..again with the R&R Letterhead.  On the first page, there was a spot for her name, age, and commitment length.  Next section asked about the subject: how many days since initial installation and how big he was.  Next section was about specific rear activity for that particular day: how long (in hours) was the subject away from the participant's rear?  How long (in hours) was he between her buttocks?  How long (in hours) was he inserted into her anus?  ?Wow?this is really exhaustive.? She said allowed as she filled out the lines.  She saw a line asking the time the subject spent in a ‘rear-alternative’.   

She wasn’t sure how to answer this quite yet because she hadn’t completely decided where the subject was going to sleep (although she had an idea of where).  The next several pages were for more detailed writing.  The first page read "Notable Interactions with subject.

~

Becca pulled out a pen from her bag and filled out her first journal entry.  Better to get it over with now, she thought, while the memories were still sharp in her mind...plus she could always add more to the journal entry later if anything else happened that night.  It took a few minutes, and when she was finished with the first journal page, she put the paper in a separate folder.  “I’ll get to the rest of it tomorrow”, she said to herself. She then put the rest of the documents back into the manila folder, the top uninspected form that looked to be about using the restroom. She had used the bathroom shortly before arriving at the lab and didn't feel the need right now, and feeling a bit overwhelmed by all the new information, she decided to tuck both the folders into her bag.  She figured she didn't need a shower either, since she had been cleaned by Laura right before the boy was put in her butt, so all that was left to do now was go to bed.  She looked at her phone and yawned...it was 9:40pm.