"You sure about this, Dash?"
"Of course I'm sure, now seal me up!" Derpy just shook her head and did as she was told, carefully making sure that the tape will be strong enough to hold while still letting air in for the box's passenger.
Dash found herself getting ever more excited as her eyes became accustomed to the darkness. Not that she had much to see, since the cardboard box only just had enough space to fit her. She shifted her legs to a more comfortable position and tried to calm herself. Last time she got so excited the box soaked through and she fell out. As she calmed, she thought of where she might end up. Manehattan? Fillydelphia? Maybe even Cloudsdale or Canterlot!
After a minute, she felt herself being lifted up. The slow bump of being carried brought a new flush of excitement, and it took all she had not to squee in pleasure. After a short canter over to the delivery wagon, she felt herself being slid into place. Her wings were uncomfortably wedged against the box, restrained from reaching their full length. The box felt like a furnace, and RD's stuck out tongue dripped with saliva, wetting her chest. She silently wondered what could possibly be more wonderful than the sensations she was experiencing, short of joining the Wonderbolts.
She listened sharply to the sound of boxes being loaded, felt the gentle bump as each was slid into place. After a few more minutes, the loading stopped and a slam indicated the door of the wagon was shut. Soon, Dash felt the wagon shift, and knew it was about to depart. It bounced around a bit as whatever pony was pulling it got used to the reins, and then smoothly accelerated to speed.
This was the first time Dash had ever tried the airmail, she realized. She figured it would be smooth, without all the gentle bumps that so tantalized her, but she swore to herself she’d at least try it. And while the straightaways were quite smooth, Dash found herself thoroughly enjoying the surprising amount of turns the driver took, sliding the boxes around in the cabin and giving Dash that amazing feeling of being completely out of control she so loved. Each slide was so tantalizing, it was almost as if she was plummeting through the air, but it was so wonderfully short-lived as the box bumped against the wagon’s wall and stopped. And every time the box behind Dash would gently nudge her, making her feel ever more close to her own body despite the space around her not changing.
She tried to wipe the sweat on her brow, but her soaked foreleg only wet her head more. Every single inch of her was covered in one liquid or another, and the box was as warm as it ever had been. Dash wished she could squeeze her forehoof between her cramped legs, just to relieve some of the pressure. She eventually couldn’t take it, and shifted to put herself against the side of the box. It had been her downfall last time, but so had not having the proper preparations. Derpy had been informed to use the tape to give the box a full wraparound, so there was no way it wouldn’t hold.
She silently enjoyed her new position for a few minutes, but soon felt the bump of a touchdown. She stopped and waited for the wagon to be opened, checking the box to make sure it wasn’t revealing anything. It was wet, of course, but nothing too terrible. She waited excitedly as the mailponies slowly unloaded the packages. Soon, she felt herself hefted up. The box caved in slightly, causing Dash to almost cry out, but it held form enough to hide its contents. She felt every last bump as the mailpony trotted to whatever destination had been set on the box. It was torture of a wonderful kind trying to restrain herself from screaming in ecstasy, and her mind swam in endorphins. After an eternity, Dash was lowered rather harshly to the floor, and her rump nearly bounced on the ground. She made a gasp and her eyes shot wide as she silently waited to be revealed. She released her breath as she heard the mailpony canter off, apparently not curious enough to check the contents.
Suddenly, a trace of fear began to grow as Dash looked around her narrow field of vision. She realized the box was pretty well secured, and it would be a harsh effort to bust out. She was contemplating how she would do it when she felt herself lifted up again. This time, however, the feeling reached all around her, almost as if she were being lifted by magic. It was a tantalizing feeling, and Dash forgot herself as she let the warmth wrap around her. As she returned to the ground, though, she realized that she was likely going to have a pony to explain to once the package opened. On cue, a box cutter emerged through the cardboard and cut a path. After a few more cuts, the box’s flaps opened.
“P-princess?”
“Rainbow Dash.” Celestia looked down into the box at the sweaty, sloppy pony that resided within. “What brings you to the castle?”
“Ah, umm...” RD quickly scrambled into an upright position and bowed. With a streak of red across her sky blue face, her eyes traced their way up the imposing figure in front of her, not quite reaching the face.
“Well?” Celestia reached forward and pulled Rainbow’s face up. “Why did you decide to ship yourself here?”
“It wasn’t really my choice...” Rainbow Dash was the most embarrassed she had ever been. “My friend just sticks whatever mailing address she can get.”
“Sounds a little dangerous. Any purpose?”
“N-none I’d like to discuss.”
“I see.” Celestia smirked. “Perhaps you can drop in again sometime. Anyway, before you head out, care to stay a while? You’d probably at least like a bath by the looks of it.”
“Th-that’d be nice... I guess.” Rainbow Dash followed the princess deeper into the castle.