http://archive.heinessen.com/mlp/thread/16315151#p16400502

A glorious morning shone over Ponyville. Birds sang and Rarity trotted along the road back to Carousel boutique as fast as her heavily pregnant belly allowed her. Twilight could say what she wanted about staying home, avoiding effort and resting in the final weeks of pregnancy, but there was no way she'd miss those specials on sewing materials at the market.
Since her morning breakfast, the foal had been way more reckless than usual. Her heavy womb churned, the foal inside kicking and while it wasn't particularly painful, she still had to stop once in a while to breathe.
"I know you want to come out soon my love". She massaged her belly gently "but can you give mommy one more week?"
Rarity only managed to walk a few feets before a terrible tightening took over her belly. She gasped, feeling a great churn and a burst inside of her womb... and then warm water running down her rump...
"Oh no... ahh... ohhh noooo... please... plea... aaah... not nooooow!"
Her plea was useless as her belly churned even more, water trickling down from her exposed pussy. She blushed heavily. The birth was beginning and she couldn't do anything about it.
She had to hurry and head back home. Labour had started and the contractions were fast. She didn't want to drop down right here in Ponyville to grunt and push her foal out where everypony could see her birthing pussy stretch. It was definitely unladylike.

With tears of fear and pain in her eyes, Rarity dropped her groceries on the road and ran to her house as fast as she could; only allowing herself to stop when the contractions and the need to push were overwhelming. She opened her front door in a hurry. Thank Celestia, she was home, and not too soon, already the foal was pressing on her cervix, its head slowly engaging in her vagina. She could only cry in pain as violent contractions tore apart her belly, causing visible ripples on her fur.

‘’Oh Celestia I can’t stop it... it’s coming out! Buck, I need to push’’. It was too late to go upstairs and labour on her bed or in a warm bath. The birth was too far gone. Rarity needed to push, right here, right now. Labour was fast, and the baby was already fully in her pussy, it's head starting to stretch her lips. Face filled with tears, she waddled to her couch, feeling the baby inside her with every movement, feeling the pain trough her body. Poor Rarity laid on her back, her wet, stretched pussy in front of a mirror so she could watch her progression. She grunted and pushed, feeling the foal slide down, the head coming out with a pop, a gush of fluid and a jolt of pain.

"Why is this happening to me?!" she cried out, feeling the foal's enormity between her legs. A push freed the shoulder, and a last one, seemingly as horrible as all the previous ones combined, saw the baby sliding out of her cunt with a rush of amniotic juice. She gasped in shock, feeling herself now so empty, her foal cries unheard as she catched her bearings.

She quickly went to catch the baby, as clumsily as she could, her humongous belly in the way, it was a colt! An Earth Pony little colt! It was a pale shade of blue and had green eyes. Of all the things she created, her baby was the most beautiful. She cried, of joy this time, as she held the precious little bundle of life, close to her breasts, still attached to him by the cord.

"Welcome to the world, my son." She gave him a kiss and levitated him with utmost care so it could suckle her teats. As it drew its first milky meal, she marveled at how... at how bucking good it felt. It wasn't like when a stallion sucked on her teats... this was unique.

But her contemplation was cut short as a jolt of pain wracked her belly... and she felt a churning inside.

"Oh no... no no no no no no! Please... ah... Please tell me I'm dreaming."

She was not, a contraction confirmed it. She cried and pushed, feeling the twin, an even bigger one; engage itself inside her already painful cunt. She pushed and pushed and pushed, but every time to foal advanced a single centimeter, it slid back inside for two.

"Pleaaaase come out already!" Her face was red from exhaustion, but no amount of whining would move the foal out of her cunt. She pushed as hard as it could, to be rewarded by the same feeling of her foal rushing out of her body after what seemed like an eternity of pain.

Rarity slowly picked it up. It was a filly, white in coat and with blue eyes like her. She propped her on her teat, but deep down, she knew this wasn't over. Her belly was still hard, big and most importantly... churning.

She was going to have a third foal, she knew it, and it would be the biggest one.

The screams of her labour went unheard trough Ponyville.