Luna awoke, uncharacteristically, in the middle of the morning, perhaps three hours after sunrise. Her head was not pounding. It was far, far beyond pounding, into a cacophony of pain that made up a constant, unending roar. With a moan, she rolled out of her bed and onto the floor in an undignified tangle of legs, wings, mane, and blankets, making a sound like an enormous sack of potatoes being dropped.

She struggled weakly, slowly fighting her way out of the blankets, and with a final heroic effort, staggered to her feet so that she could dunk her head into the bowl of water on her nightstand. When she ran out of breath, she raised her head just enough to get her nose clear of the surface, then began sucking the sweet, sweet water greedily down.

When the bowl had been licked dry, she slowly raised her head again, her eyes squeezed down to slits. What had she done to herself? Her brow furrowed a little further as she struggled to remember, and she looked around her room for any clues. Her eyes settled on an a pair of empty bottles, strewn haphazardly near the fireplace, and she got to her wobbly hooves to make her unsteady way over to them, to see what they were.

Applezap, read the top of the label, with Fruit Alcohol below, and a reassurance that it was Distilled from 95% Selected Apples. That would more than explain her head, at least, but why... would... she...

Luna's heart and expression sank, as more of her memories began to bob up through the fog of last night's consumption. She remembered, now. Oh, Moon, she remembered. Moon, hah! Hahah! She'd be back there soon enough, as soon as Celestia caught wind of this! Oh stars. She half-sobbed to herself and sank back to the floor next to her failed memory erasers.

Before she had a chance to even think about what she could do next, there came a knock on the door, and a soft voice calling her name. It was Twilight, and that was much, much worse than if it had been Celestia.

“Luna,” called Twilight again, “Are you in there?”

Luna curled herself up into a ball and thought thoughts of nonexistence, willing Twilight to pass the room by, and go looking somewhere else.

“Luna, I'm coming in, okay?”

Her heart was somehow a block of ice, and beating like a hummingbird's wings at the same time. She curled up tighter, hiding her nose under her hind leg and covering her face and head and neck with her wing.

She heard the door open. A few hoofsteps, and she shivered involuntarily. A gasp, the sound of running hooves, and she tensed up, trembling all over, waiting for the inevitable.

The hooves skidded to a stop behind her, and suddenly there was a warmth against her back, the feel of a foreleg across her shoulders, a wing hesitantly settling over her body. Luna flinched, and a litany began to spill from her mouth.

“...sorry, sorry, sorry, sorry, we are so sorry, please...”

She tuned in to Twilight's voice again, which was coming out in a quiet rush as its tone turned to confusion.

“--'s wrong, Luna? Please tell me! Are you alright? Are—what are you sorry for? Luna?”

“..sorry, sorry, please...”

“Luna—what? Are you—” Twilight cut herself off, huffed, and with a quiet hum, gently pried Luna's wing up with her magic.

Luna's eyes were pinpricks, frozen in fear as their gazes met, and Twilight sagged. Then, hesitantly, she bent down, and pressed a kiss between them. When she pulled her head back, Luna's eyes were wide again, staring back at her in disbelief, and Twilight blushed and looked away.

“I never said,” she murmured, “that I didn't like it.”

Author's Note

Prompt #538: Last night, two ponies kissed for the very first time. What happens today?

Title is a modified lyric from Auld Lang Syne.

Slight edit from how it went out to TMP: 100% changed to 95% for referential humor purposes.

Apparently Luna's panic didn't make sense to the TMP folks, so let me lay this out to anyone who is similarly confused: last night, Luna drunkenly kissed, with wild abandon, the one pony who had become her friend, who also happens to be the one pony whom (Luna feels) Celestia cares for most in the world. When Luna stopped kissing, she saw a big, wide-eyed look on Twilight's face, panicked, and fled back to Canterlot to drown her mistakes in Pure Fruit Alcohol, and that is where Twilight catches up to her the next morning in the above story.

The magnitude of her panic is the point of the story: it's irrational and overblown, because it's born of lingering guilt for the Nightmare and a rock-bottom sense of self-worth born from the same. The fact that she's panicking is supposed to be suggesting something about the sad state of how she sees herself, but apparently that didn't get across. I don't know whose fault that is.