The music link at the beginning links to something that has either been taken down, never existed, or has been blocked in my country.

"Uh...sure." She replied, half expecting her to put the closed sign up. Instead, she was treated to Rarity casually toss off her skirt with a bit of magic as she started unbuttoning her shirt, revealing a pair of plump 39D-cup breasts, hidden behind a sheer blue lace bra. When that fell, Barb caught sight of a matching pair of thong panties that showed off her surprisingly long legs.

tossing

Why is it that, here, you specify that it's 39D-cup? You didn't specify it for any other character, and when you introduced Barb you said "E-cup" without the 40 that would be mentioned later in the chapter. That case, the 40E-cup mention, makes sense because it's Rarity speaking, but why mention that Rarity's breasts are 39D in narration when you don't specify Barb's cup-size in dialogue?

A few minutes later, she came back carrying a large stack of pancakes, covered in raspberry syrup. "Wow that looks good!" Barb licked her lips at the sight. Though, she wasn't quite prepared when Pinkie plopped down in her lip, wiggling a bit to get comfortable.

Barb had to bite her lip to keep from moaning. She wasn't sure how, but Pinkie had managed to make it feel like she had just ground right on her bare crotch. 'Faust, how's she do that!?'

"Open wide!" She smiled, holding up a forkful.

Barb looked at for a sec before she just grinned a little and opened her mouth. However, what they both forgot is that syrup can, and will drip if you aren't careful. And Pinkie had put a lot on the pancakes. By the time she bit down on it, a fair bit of the syrup had fallen onto her breast. "Oh crud!" She muttered, glaring at the sticky mess. "I need a napik or something...!"

"I got it!" Pinkie leaned in and ran her tongue of Barb's chest, getting the syrup, but also sending a shiver up her spine.

"P-Pinkie...!" She yelped, her face one again bright red.

"Yummy." Pinkie purred, licking her lips.

"Wha..?" 'Now PINKIE'S doing this!?' She thought, absentminded taking the next bite Pinkie offered, shuddering again when Pinkie dove into her cleavage again. 'A girl could get used to that...but...why??'

lap

"how's" is not a contraction of "how does" or "how did" but rather, it's a contraction of "how is". If you want to keep it a contraction, you can use "how'd" because that is a contraction for how did, or you can just say "how does" or "how did" instead.

"at her for" or "at it for"

I didn't know that Napik brand carabiners were capable of cleaning up messes. I thought they were looks used for holding things, often used by mountain climbers. But, in seriousness, I think you meant "napkin"

once

absentmindedly

Before long, the pancakes were done. "Now..." Pinkie's voice turned husky as she flicked the plate into the sink -and somehow landing it with breaking -, "Time for the main course." She quickly turned to straddle her, wrapping a leg arunf the back of the chair.

landed it without it breaking

around

In the window she could see Rarity getting her workbench set up for the day.

Was It wasn't a quick peck; no, this was a full-on, lovers-style kiss, complete with one hand gripping the back of Barb's head!

Why's she being so forward?

It feels like it was just yesterday when you were trying your first fireball cinnabon pie!“ (——

when Pinkie plopped down in her lap,

Barb looked at it for a sec

Pinkie leaned in and ran her tongue off of Barb's chest,

She yelped, her face once again bright red.

She then went in for the kill by adding puppy dog eyes.

'Well...it-its only fair right...?'

and somehow landing it without breaking

wrapping a leg around the back of the chair.

Barb nearly shrieked once she made it out of the bakery.

While the suggested corrections are accurate, and it'd be good to get this proofread, it looks somewhat off to have the only comments on this story be editing errors. It'd be good to have some mentions that, for example, it's really very hot and fun to read So thank you for writing this!