You can't be serious, Tia!
It began like any other day in the castle; the two sisters bickering with each other as they passed each other, various bills and favors that a few ponies wished for her to look over, and of course, her own free time in between those activities, the majority of it spent eating moon pies and preparing for the one moment that she was looking eagerly to; tea time with her sister, for the first time in a thousand years. It was a long standing, unspoken tradition between the two to have tea time together during certain days, and Celestia had continued to honor that tradition even when her sister was banished to the moon, which deeply touched Luna's heart; she expected Celestia to stop drinking what she called 'liquid chaos' and hope that Luna forgot that tea ever existed in the first place. Ha! No such luck for Celestia.
Although her sister quite frankly hated tea and only really enjoyed the refreshments that came with the tea, Luna adored the beverage; there was just something about a brewed, herbal drink that calmed her nerves and made her feel energized for the rest of the day, or night, in her case. It was a pity that her sister was far more interested in the crumpets and cake that accompanied the tea, but at least Luna got most of the tea to herself, which was fine by her.
Humming a little tune from years bygone and with most of the words forgotten, she strode into the royal gardens, and began to navigate through them; while it was true that she could fly up and more easily locate her sister, it was agreed a long time ago that it would have most likely have drawn unwanted attention to them, which would have more than likely disrupted their sacred ritual of Celestia scarfing down all the cakes and crumpets while Luna drained the entire pot of tea in one go. Ah, good times, good times.
Her instincts told her to go around a bed of lilies, straight for a few minutes, and then to squeeze through a particularly narrow entrance to a side-area that was hidden quite cleverly behind an unassuming willow tree. She followed the instructions exactly as her instincts had told her, and lo and behold, was Celestia with her regalia placed in a nice, tidy pile slightly aways from the table placed in the middle of the small side-area, made to accommodate two alicorns. Grinning, Luna strode forward, levitating her own regalia off slowly and settling them down next to Celestia's pile before joining her sister at the table.
"It's about time you got here, Lulu, I was afraid of starting tea time without you!"
"Ha, as if! You need us...Me to drink all the tea for you, Tia!"
Celestia was about to reply to her sister, only to get cut off as Luna continued on, not noticing that her sister wanted to speak. "In any case, I hope you remembered my favorite kind of tea, Tia!" At this, Celestia nodded slowly, with a faint smirk on her lips.
"Yes, of course, the teapot is full of white peony, Lulu." At this, Luna pumped a hoof into the air, and immediately began to pour herself a cup of the tea she had missed so, so badly. As she began to drink the revered tea slowly, wanting to savor it, Celestia began to pour herself some of the tea into a cup of her own, and started her own drinking, although it was at a much slower pace than her sister's.
As Luna finished her first cup, she noticed that Celestia actually seemed to be enjoying the tea; then again, it was probably just out of politeness; after all, this was their first tea break in a long, long time, but she missed any of her sister's usual comments about the tea tasting like vile, rotten bananas. She reached forward for a cookie, fully expecting her sister to slap her hoof and declare that the cookie was hers, but oddly enough, she merely watched Luna with amusement twinkling in her eyes. Confused and suspicious, Luna brought the cookie to her mouth, and bit off half a mouthful from it, chewing slowly as her sister continued to nurse her cup of tea. Strangely enough, the cookie tasted just fine, but most troublesome of all, her sister did not challenge her for it!
As she thought about what this strange phenomenon could mean, Celestia levitated the teapot towards her, and to Luna's surprise and horror...
Poured herself another cup of tea.
"WHO ARE YOU AND WHAT HAVE YOU DONE TO OUR SISTER?!"
Celestia groaned as her teacup shattered, and she levitated up another tea cup while glaring at her sister in a way that made Luna wilt slightly from the intensity of said glare.
"Things change over a thousand years, Luna, I thought that would have been obvious enough."
This was...New. Something she had never expected to happen did indeed happen, and she didn't know if she needed to be scared or not because of this strange new development; Celestia, drinking more than one cup of tea? What was this madness?!
"You...Truly enjoy tea now?"
"At first I hated it, but over time, because I have kept up this tradition of ours, I suppose I have gained a tolerance and a slight affection for the beverage, yes."
"Do you...Still harbor as much greed for refreshments?" At this, Celestia's eyes narrowed slightly.
"I am willing to share a few, sister, but you have another thing coming if you think I'll willingly part with many of them."
"...You can't be serious, Tia!"
"I truly am, Lulu."
After figuring out that her sister truly did seem to have a fond side for tea, Luna poured herself another cup of tea, deciding to accept this new development, and the two enjoyed a relatively peaceful afternoon in each other's company.