This was such a lovely surprise to open up my box to; thank you, anon <3 I've honestly been sitting on this for days thinking about this very seriously...bear with me as this may or may not answer your question:

In the timeline of the universe, they've been dating for almost two? years, which is really serious for both of them.

So, Felix invites Jisung to spend Christmas Eve with her and her family. Christmas Day is definitely a day for families to have the day off, relax, exchange presents, etc. But Felix explains Christmas Eve is almost as important than any other part of Christmas—she and her parents get dressed up, have a late, elaborate seafood dinner, then stay up and head tout o the church for Midnight Mass.

Jisung's intrigued—it's the first time he's going to meet Felix's parents, too. So she makes sure he wears a suit (which Jisung has to borrow one from his dad, and his mom says he really should have one of his own at his age!), and Jisung makes sure he brings a nice bottle of wine (imported from France!), his hair is combed away from his face, and he genuinely has to make sure his heart stays where it needs to be, not in his throat or trying to crawl out of his ass.

Felix's family is so kind—her sister and her family are there for dinner, too, but only the four of them head over to Midnight Mass. Her sister went earlier for the children's mass, which they heard all about, and the kids loved getting to see the animals around the manger outside.

The closer it gets to mass, the more nervous Jisung gets, because he has no idea what to expect—and his gift is also burning a little hole in his pocket. He had Jeongin bring back a little bit of Holy Water from his retreat to St. Peter's, and he also got her a bracelet she'd been eyeing at a kiosk in the mall from a couple months ago—he hopes she still wants it.

Mass is interesting—Jisung never thought he'd see a church packed, full of people wall-to-wall, in the middle of the night. The way the lighting illuminated the space within, the night sky painting the windows in black, the altars looking even more divine with the electric candles flickering up the marble pillars. Jisung's honestly a little tired from the three glasses of wine, and Felix smells so, so good in the new perfume he got her for her birthday this year, but when the service starts, his drowsiness escapes him— between all of the standing, the sitting, the kneeling, the singing, the listening....He has no idea what to do, but he follows Felix's lead, awkwardly waving his hand across his face each time he sees everyone else do it, a beat behind.

The funniest part is catching Felix's dad nod off near the end, when the Father is chanting an endless list of names in prayer. Felix's mom pokes him to keep him awake, while Felix has to stifle her own giggles. And when it's all over, they run into other parishioners—family friends Felix has known since she was a little girl, and them commenting how beautiful she is, and he sees how proud Felix is to introduce Jisung to them. And in that moment, Jisung feels a warmth in the pit of his stomach—less a fear, and more of an assurance, that he feels just as proud to be her boyfriend, too. That coming to see how she spends this holiday with her parents, in the place she's spent so much of her life being raised in....that's like, so crazy.

And then they get home, they offer Jisung the couch, but he insists he's okay and calls a car home, insists he needs to help his cousin with elf duties, and promises to call Felix tomorrow when they're ready to open gifts. He has to bite his tongue and just sleep on how special it was for Felix to share this night with him, though—that this was a gift in and of itself, not just the neatly wrapped boxes she shoves in his arms on his way out.