Fluttershy woke up in her cozy bed after a long sleep. She stretched her wings and let out a loud yawn. Yesterday was very busy - it was cleaning day for her animals, and it took whole day to finish the work. Some creatures, like rabbits, were easy to clean, but washing huge bear who really wanted to hug and play was a hard chore. But now, Fluttershy have a day off, so she can rest the whole da-
-CRASH!!!-
With loud noise something fly thru the open window of Fluttershy room and crash on the poor pegasus on the bed. On top of Fluttershy was laying her best friend and one of the strongest ponies she knew - Rainbow Dash. She quickly shook her mane fool of dust from the crash and looked at scared pony
-You have to admit, that was amazing entrance!-
Fluttershy was slowly calming down from the crash
-It was, uhm, cool, but I prefer when you use the front door- she said quietly.
-I know I know, but right now I have something urgent to ask you about-
Rainbow eyes were shining frim excitment.
-What do you want to ask Dash?-
-I need to swallow you whole-
-…-
Yellow pegasus thought that she overheard something. She stood in place with open mouth, looking at her friend. It took a few minutes until Fluttershy realized that Rainbow was being serious about her request.
-W-what? You want to eat -I mean- swallow -ME- whole? But how, its just a prank, right? I am sure that Pinkie convinced you to tell me tha-
Rainbow Dash placed a hoof on Fluttershy mouth
-Wait a minute. Let me explain. I was chilling in my training room, and I was thinking how I can improve my workout. Then I realized that I can train more if I had more heavy equipment on me! But I dont have so much money to buy it
-Ekhm, Rainbow-
-so I started flying around Ponyville to find something different and I saw you cleaning the snake, and I thought
-Rainbow?-
-if snakes can swallow other animals whole, why shouldn’t I do this? It will be cheaper than gym equipment and-
-RAINBOW-
Fluttershy raised her voice a little, making her friend stop with her monologue.
-Sorry, I get carried away. So would you be okay with that?-
Fluttershy was still confused, not knowing what to think about it.
-Rainbow, even if you can do swallow somepony whole, are you sure this is 100% safe? I am kinda scared, this isn’t something that I usualy do-
Fluttershy didn’t know what to think about her friend request. She likes Rainbow Dash a lot, but to be inside her stomach for entire training sounds too risky
-Come on Fluttershy, my belly is the safest place in all of the Equestria! All the time you will be close to me, and after I finish I will let you out. I promise you that!-
Still unsure, Fluttershy looked at her friend. She know that Rainbow would do anything cor her.
-Arlight. You can swallow me-
Fluttershy couldn’t believe what she was saying. It sound so bizzare and weird, but if she can help her friend, she will do it.
-Awesome! Okay, here I go!-
Rainbow opened her maw, with wet tongue and white teeth, and started moving it closer to the Fluttershy uncertain face.
-GULP- Here I go…-

-Ough-
-Ugh-
-Ow-
Fluttershy was vigorously thrown against Rainbow Dash stomach walls. She wanted to help her friend, but she didn’t knew that the training was gonna be so intensive and fast. Although only 15 minutes have passed, inside the belly was too dark, cramped and wet for poor Flutterhsy.
-Uh, Rainbow, I think I want out, I know that I was supposed to be here for 2 hours but I dont feel safe anymore-
At this moment Rainbow Dash let out deep and loud BUUUORRP, emptying her stomach from the air and squeezing poor Fluttershy inside.
Rainbow was waiting for Fluttershy to say something, but from the outside she could ony hear blorping and other sounds of her belly.
-Remember to tell me if you want something-
Rainbow patted her full belly and resume her training.
She was sweating and jiggling while doing lot of different excerisces. Push ups, squats or even flying was much more difficult with full grown pony inside, but it was just the thing that Rainbow wanted. After doing 100 squats, she sat on a bench and let out huge belch.
-Dont worry Flutters-BUUORP-, I will let you out after the training. Hold on for an hour in there!-
Rainbow said to her belly while rubbing it. She didn’t thought that having another pony inside is would be so satisfaying.
-Rainbow, I really want to get out! It isn’t funny!-
Fluttershy tried to draw Rainbows attention by punching the walls of her stomach, but Dashie was too focused on a training to feel any form of protest from inside of her stomach. Meanwhile inside the belly the acid and fluids started to rise up with dangerously high speed.
-Oh dear…-

-UOooORP!-
-Oh my, that was a big one. I feel so tired, but damn, it was such a good workout! I need to use this training method more often!-
Rainbow Dash burped loudly, not noticing yellow feathers and pink hair that came out of her mouth. She was too focused on her new gains, admiring her sweaty and muscular body,she even looked more ripped than Applejack. Rainbow body was similar to a ancient stone statue, of course if you ignore the fact that the lower half of her body had plump rear and huge bloated belly, which sloshed with her every move. 4 hours ago inside that belly was Fluttershy. But now inside the belly Fluttershy remains, mixed with stomach acid and protein shakes, were sloshing loudly while Rainbow admired her body. Fluttershy become fat on Rainbow body, enlarging her hips, butt and belly.
-That was intense!-
Rainbow started to rub her bloated belly, thinking that her friend is still inside.
-Thanks Fluttershy for being my training buddy, you can come out noUOOOOOORRP!-
Rainbow whole body shaked from the strenght of her own long burp. Her belly was swaying like a full water ballon and her thighs were jiggling. When she finished, she waited for the response of her friend. Instead she hear loud -BLORP- and -SLOSH- coming from inside her bloated stomach…
-Fluttershy?-

Check out my Twitter for more art!
https://twitter.com/Hurb_69