Archivist's Notation: For the sake of argument, clarification, and my sanity allow me to explain I am writing under the assumption all ponies can grip things with their hooves via magic and willpower that requires no further explanation.
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To the Cakes having Pinkie Pie live and work with them at SugarCube Corner was one of those things that fit and made sense to the Cakes. Granted some of things Pinkie did made no sense and there were times when she would cause a strain on their patience, but honestly the Cakes wouldn't have it any other way.
She really was like the energetic and hard to predict daughter they never had, but there was always one thing that was consistent with Pinkie Pie: she was always interesting to pause and watch work her magic as she planned out her parties. Well that and her love of helping take care of the Cake twins, but that's a story for a different episode.
So Mister and Misses Cake weren't exactly worried when Pinkie bolted into the shop and darted up the stairs excitedly talking a mile minute about, "So much planning! So much planning! So much planning!". The Cakes merely exchanged amused smiles at her antics, before Pinkie came back down with her party planning kit.
So after tending to the small group of afternoon customers the Cakes paused to watch with quite a bit of interest as Pinkie sat at a corner table she had commandeered and covered in various papers, pencils, and a magic eight ball. Pinkie was clearly "in the zone" as she quickly scribbled out a letter then scrunched up her face in concentration mumbling quietly as she carefully proof read what she had written then smiled and resumed her writing.
"Pinkie dear what are you doing?", Mrs. Cake asked curiously as a napping Pound Cake snored quietly as he laid on his mother's back.
Pinkie smiled as she looked up and twirled her pencil on her hoof, "I'm writing out invitations to my cousins for a Cousin Reunion Party next week."
"Oh, which of your cousins will you be inviting over?", Mr. Cake asked as he trotted up to the girls as Pumpkin Cake sleepily nommed on his short mane.
The Cakes were familiar with Pinkie's various cousins through the numerous letters and excited dramatic readings of said letters that Pinkie would give when she received news from her beloved kinfolk.
"Well I'm inviting three of my four favoritest cousins to be specific", Pinkie smiled as she turned to face the Cakes, "I'm inviting Solution Pie, Surprise, and HB."
Misses Cake nodded as she recognized the names from Pinkie's past descriptions, "But Pinkie I thought you told us they didn't exactly get along with each other?"
Pinkie sighed as she turned back to face the table covered in stationery and a over head picture of Ponyville for some reason, "Yeah they do tend to get grumpy and snappy if they spend too much time together, buuut we haven't seen each other in like three years so I think it should be okay for them to spend like a week together without too much fighting. At least I hope so", Pinkie finished lamely.
Mrs. Cake gently passed the sleeping Pound Cake to Mr. Cake to take up to bed for their afternoon nap then turned back to Pinkie, "Well dearie, in my experience, with catering, if there are family members who tend to argue its usually best to keep them preoccupied so they don't have time to argue with each other", Mrs. Cake suggested as she sat beside her goddaughter.
"So if I plan out all sorts of games and stuff to take up a lot of time they won't have the time to argue?", Pinkie ventured as she rolled the pencil under her hoof.
"Exactly", Mrs. Cake affirmed with a nod.
"That's a great idea! Thanks Mrs. Cake", Pinkie chirped as she hugged Mrs. Cake.
"You're quite welcome dearie", Mrs. Cake smiled as she patted Pinkie on the back, "Just remember the rules on having one of your parties at SugarCube Corner: Be sure to clean up afterwards. Don't use cooking supplies that are marked for clients. And.."
"Make sure everypony has a good time!", Pinkie finished with a wide smile.
"Precisely", Mrs. Cake smiled as she got up from the table, "Now don't stay up too late Pinkie I may need some help with an order for five dozen crumpets tomorrow."
"I promise won't stay up too late Mrs. Cake", Pinkie replied before she resumed writing.
------ Later that night ------
Pinkie laid in her bed on her belly rear hooves kicking in rhythm to song she was humming as scribbled out a few ideas between bites of popcorn as Gummy nommed on her poofy mane occasionally.
"Hmm Surprise and HB would probably enjoy a good afternoon of pranks, but Solution might be hard to pry out of her books. So whatcha think Gummy?", Pinkie asked her oddly eyed gator as she held out a piece of paper with a dozen or so activities scribbled out in pink ink.
Gummy for his part blinked out of sync then snapped at the left corner of the list of activity ideas before Pinkie pulled it back and looked it over.
"Hmm good point Gummy", Pinkie replied(?) to Gummy as she crossed out a couple of ideas where he had snapped at the paper, "I should plan out some stuff all three of us could all do together."
Pinkie continued scribbling out ideas and plans as she hummed to herself while three envelopes sat on her night stand each bearing a different mailing address, but each bearing the same town and country destination: Tumberville, Equestria.
----- The next morning -----
SugarCube Corner's mailbox opened with a metal squeak, as usual, when it was opened to receive the day's mail. Normally the mailbox was empty unless Pinkie forgot to check it for the Cakes or if Pinkie decided to give Ditzy her morning muffin personally by popping out of the mailbox.
However, today there was no lonely forgotten mail nor was there a pink spring powered pony-in-a-mailbox to launch out at her this morning. Instead there was, to Ditzy's pleasant surprise, a pipping hot orange cranberry muffin on a plate sitting on three pink envelopes with a small note saying "Special postage payment for the best mailmare in Ponyville!"
While Ditzy prided herself on her quality work with the EPS and had memorized the entire Postal Service Hoofbook and knew that accepting gifts while on duty was clearly against regulations Ditzy knew she had special permission from her boss that if it involved Pinkie "it was not to be considered a regular incident subject to regulations as dictated by the Hoofbook. So just eat the muffin there and quit bringing them into the office!"
So with that in mind Ditzy paused her route to sit and enjoy her special edible postage as she carefully read over the addresses written on the pink envelopes.
"Tumberville, huh?", Ditzy questioned as she counted to make sure there were the correct number of stamps.
She tapped her chin trying to remember the policy on that destination since she accidentally broke the Tumlberville mail portal box last Tuesday with that large ticking singing package.
"Hmm I guess I'll ask if the Doctor can help me delivery these since the special mail box is broken", Ditzy shrugged as she slipped the letters into her saddlebag, "Oh well I doubt it can be that hard to use the TARDIS to help me deliver three letters to Tumberville."
Ditzy hummed a happy tune completely unaware of the severity of the jinxing her statement would cause.
End of Chapter.