It was Sunday night, and in the Postal Service House, that meant only one thing:
Bath Time.

School the next day for Dinky, and the Workweek resuming for Ditzy meant both ponies needed to wash up and look their best in the coming morning. There was just one problem:

Dinky didn't want to have a bath, and Ditzy was perplexed at how to convince her she needed one.

The unicorn foal had been playing all day long in the fields with some of her friends, trying out harmless magic tricks, playing tag with bunnies, and even helping the Apple family eat some of their overstocked apple goods at lunch time. She'd even brought home a basket of apple bran muffins for her mother; which was Ditzy's favorite snack. Together they had shared the basket, and Ditzy, though hardly articulate, had thought to herself over the little meal, 'My, how much fun Dinky's had, but /MY/, how dirty she's gotten!'.

But, when it came around to bath time, Dinky was adamant:
"I don't wanna take a bath, mommy, I want to play s'more with my dolly!"

And so, Ditzy sat, watching her little daughter play with the doll that had once been her own when she was Dinky's age, and pondered. Maybe if she promised her more muffins? But no, it was rather late to go bothering Granny Smith for some muffins. Maybe if she promised her an extra bedtime story? .. Well, no, that would do no good, for it was usually Dinky reading the stories to Ditzy, and though Dinky always had so much fun, two stores might just wind her up again instead of help her sleep!

She put a hoof to her cheek as she thought, tapping it, trying to force her thoughts to coalesce into an epiphany. Think, think think.

As she did this, she watched Dinky pull her bubble bottle from her toy box, and then start to pretend that her dolly was blowing bubbles.

Bubbles. Suddenly, it dawned on Ditzy, and she smiled ecstatically. Of course!

Within around twenty minutes, Ditzy was ready with her ingenious plan. She came creeping out of the bathroom, calling happily, "Muffin! Come see! Surprise for you!" She beamed happily. Dinky was a little wary at first, because she'd never thought of surprises in the BATHROOM before, but, she carefully capped her bubbles, and left her doll in a safe place, before she went to join her mother.

And /oh/ the surprise.

The entire bathroom was filled with bubbles. Dinky gasps in surprise at this; realizing both at once that this was the most bubbletastic sight she had ever seen.. and that her mother must have used a whole bucket's worth of bubble bath!

Which, of course, Ditzy had indeed done!

"Oh Mommy," Dinky finally said, "It's wonderful!"
"Bath?" Ditzy asked, hopefully, to which Dinky eagerly nodded.
"Yeah, let's have a bath together!"

And that's exactly what they did.