i'll keep you in mind, from time to time
"Dipper!"
Dipper knows what he's going to see before he opens his eyes. It's Christmas morning, which means there's only one real possibility. So instead of giving in, he squeezes his eyes shut more tightly and tries to roll over, which proves to be impossible with Mabel pinning him down.
She starts shaking him. "Dipper-Dipper-Dipper-Dipper," she warbles.
There's no point in getting up. The sun hasn't risen yet and their parents won't even consider opening presents until at least nine. Dipper already made his way downstairs just after midnight to retrieve his stocking, as is tradition, and Mabel's was gone when he'd gotten there (she usually times midnight down to the second, whereas he descended at a more leisurely 12:04). He prefers to stay in bed and sleep until the allotted time rather than torture himself by camping out near presents he's not allowed to touch.
Mabel, however, has likely been kept awake for most of the night by a steady diet of stocking candy and Christmas excitement, and she is determined to not suffer alone. Which leaves Dipper gritting his teeth and remaining limp as she shakes him. He manages to maintain his act right up until she begins poking his sides.
He can't contain his ticklish laughter and surges upwards, knocking her to the foot of his bed. He bundles his comforter around himself protectively. "Mabel, go back to bed," he orders.
She yawns in a suspiciously fake manner. "Yeah, okay, I guess you're right. I'll just go back to bed," she mumbles, pushing herself up onto her feet.
But Dipper knows her too well. He swiftly reaches behind his head and relocates his pillow to his front just as Mabel launches herself up and over the barrier of his knees. Their tussle is silent save for the scratch of sheets and blankets; ever wary of their sleeping parents, even Mabel makes nary a sound as she tries to tickle him through his cloth armor.
Once again, Dipper's growth spurt comes in handy. He overpowers her long enough to catch her with a side swipe from his pillow that sends her tumbling off the bed. She hits the floor with a thump that reverberates throughout the house and rattles the door to the room.
Dipper's mouth drops open and he releases his pillow guiltily. "Geez, Mabel, are you okay?"
"Why are you so strong now?" she says through the hair that covers her face. Her tone of voice clearly implies that he's cheating somehow.
It became apparent to Dipper a while ago that three months in the rough and tumble forests of Gravity Falls have done his slim physique at least a few favors. Remembering the lessons of the Manotaurs, he's been applying himself in PE for once and even makes use of the school gym equipment on occasion. Mostly, he does pushups in his room. It's less about trying to be more manly, as he'd once so desperately wanted to be, and more about keeping hold on a part of Gravity Falls that is still with him. He's changed in a lot of ways, and he doesn't want to change back in even one.
"You know, just pumping iron. Blasting my quads," he tells her offhandedly (he has no idea what he's saying).
She sits up, her hair falling away to reveal her discontent. "Mabel no like."
"Yeah, well, Mabel doesn't have to like. I have to build a monster-hunting physique," he says a bit self-importantly. "I can't go back to Gravity Falls all noodle-armed again."
Mabel seems to accept his reasoning, head beginning to nod. Then her braces make an appearance in a grin that immediately puts him on the defensive. "Or…" she says, drawing it out, "…maybe there's another reason. Something else. Or should I say, someone."
"What are you talking about?" he says warily.
"'Hey, look at my big strong arms, baby, they're for punching monsters,'" she says, lowering her voice in a very demeaning impression of him. "'Pacifica, I just want to kiss the pillow you slept on and pretend it's your face!'"
"Give me that!" he says, snatching the pillow back from her.
"Sorry. I wasn't trying to steal your girlfriend," she says impishly.
"Ugh, Mabel. Quit being gross. I don't kiss my pillow."
"Yeah, it doesn't look much like Pacifica. I have some yellow yarn you can borrow if you want to kiss that."
"I'm not kissing anything!" Dipper knows she's trying to get a rise out of him to even the score, but he can't seem to stop himself from reacting.
"You and Pacifica sure spent a lot of time alone in here…" Mabel muses.
"While she totally fell apart," Dipper snaps.
Mabel immediately looks remorseful. "Poor Pacifica. She really was falling…"
"She was a mess."
"…right into your arms."
Dipper collapses back onto his bed and lets out a long breath. He's entirely used to Mabel seeking out (and often forcing) romance wherever she thinks it can be found, but it doesn't usually involve him. And after the disaster that had been his single sort-of date with Candy, he'd thought Mabel had learned her lesson. Wishful thinking, apparently. Not that he thinks she's serious about him and Pacifica. Probably. Maybe.
Actually, he has no idea.
He rolls over and stuffs his head beneath his pillow. "Wake me up when it's presents time."
"Booooo!" Mabel opines. "Entertain me! I must be entertained!"
Realizing that sleep is a hopeless dream, Dipper finally gets out of bed and turns on his TV. He and Mabel are deeply embroiled in a cooperative puzzle game when they finally hear the water running in their parents' bathroom, signaling the proper start of the day. Mabel promptly begins failing the game in various spectacular ways, unable to sit still or concentrate. Dipper sticks it out for a while, but he can only take so many checkpoint restarts. He drops his controller and waits.
"What do you think we'll get?" she says excitedly. "Another set of Foam Whackers? Giggle Time Bouncy Boots? A new pig friend for Waddles?!"
"Five bucks on socks," Dipper says.
"Dipper, did you ask for socks again?" Mabel says in the same tone their mother uses when she's not mad, just disappointed.
"I don't ask for them. I just get them."
"Well, maybe if you didn't always ask for expensive video games, Santa would bring you a better variety."
"Santa isn't real, Mabel. Mom and Dad buy our presents."
Mabel raises an eyebrow at him. "Are you sure?"
After all he's seen in Gravity Falls, he can't honestly say he is. He leans back far enough in his beanbag to see the clock on his desk. "Come on, let's go sort the presents before Mom and Dad go down."
Mabel loves sorting the presents. She takes to the task with her usual zeal, handling each package with reverence and wallowing in the atmosphere. The tree is covered in lights and tinsel and innumerable ornaments, each one shiny or goofy or a keepsake, each one with a story attached to it (Mabel knows them all). She is surrounded by brightly colored paper with reflective surfaces or cute illustrations of snowmen and gingerbread houses, inundated in springy bows and stickers with glitter and carefully written names. Dipper sort of helps, but mostly he just gives her space to work. She is in her element.
When she finishes, Dipper sees that both of their piles seem a little bigger than usual. He checks the present on top of his; it's from Soos and Melody. Digging a little deeper, he finds two more boxes, both of which are unwrapped. One says it's from Grunkle Stan—the other, from Great-Uncle Stanford. Dipper grins at the deception, even as he feels a small pang of guilt. As far as his parents are concerned the presents are from the same person. It doesn't feel fair that they don't know how their family has changed, but Dipper doesn't think it's his place to tell them.
Mabel gives him a knowing look: she's noticed, too. Whatever she feels about the situation is quickly subsumed beneath her manic Christmas cheer, however.
Dipper gets the usual assortment from his parents: a couple new video games, some more RAM for his computer, and a bunch of clothes he didn't ask for. Mabel always gets substantially more presents than him because most of what she asks for are crafting supplies and she intentionally keeps her requests as separate as possible to maximize her present-opening opportunities. To her, receiving a present is a present in and of itself. It's tradition to take turns and usually Dipper ends up waiting and wishing she'd finish up already so he can try his new games. This year, though, he's got a few more presents than typical, and he's saved them for last.
Soos' present turns out to be a shirt, which would normally be disappointing; however, in this case it's an improved version of Pterodactyl Bros and the shirt is the right size to fit. Melody has a sister who is an artist and she took Soos' crude rendering and turned it into a truly awesome work of art, with Soos and Dipper side by side defying the pterodactyls menacing them from a prehistoric sky. His parents don't get it at all, other than in some kind of inside joke, ironic sense, but Dipper immediately wears it proudly.
Mabel's eyes fill with tears when she opens her present from Soos. It's an entire stack of photographs of the Shack: the grounds, the museum, and the living areas, all ready to be used in a collage or whatever project she wishes. There's also a flash drive with digital versions in case she wants to reprint any of them. She is immediately captured by them, slowly turning over each picture with a sense of nostalgia intense enough that Dipper can see his parents' confusion and the beginnings of concern.
He quickly scoots over and gives Mabel a hug, saying, "Nice, Mabel!" When he pulls away, he surreptitiously pushes the pictures towards her lap, silently urging her to put them down. She takes the hint, placing the pictures back in their box as she wipes at her eyes and turns the wattage on her smile up a bit too much to be entirely genuine.
The presents from their grunkles are next. Dipper receives a copy of Anomalous Phenomena from Ford. His present from Stan is in a heavy locked metal box. Dipper uses the provided key, peeks inside, and promptly closes it. He exclaims how nice it was of Grunkle Stan to give him some tools of his own, since he'd gotten used to working around the Shack with Soos—it's actually the chain mace he'd once taken on his hunt to capture a Shack attraction for Mabel. He'd ended up inadvertently trapping a Gremloblin, a creature roughly ten times more dangerous than anything he'd been expecting, which is an anecdote he is not going to share with his parents.
Mabel also gets a book from Ford, though hers is less technical. It's a book of scientific explanations for everyday things, and it's full of informative pictures and fun experiments that can be performed with household items. Dipper can already see the next several of her 'Mabel's Guide to Whatever' forming in her head as she flips through the pages. Her present from Grunkle Stan is an entire roll of each kind of bumper sticker sold in the gift shop. Mabel promptly sticks one to her sweater and another to Dipper's toolbox.
Altogether, it's a pretty excellent haul. Dipper eats coffee cake as he surveys his bounty, pleased and eager to really dig into it. He suddenly wonders if it's snowing in Gravity Falls. All the pine trees will make the whole valley feel seasonally perfect. They make big enough Christmas trees that even Pacifica's massive pile of presents would fit under them.
Then he feels bad when he thinks maybe that isn't the kind of assumption he can make about her life anymore. Maybe she's alone. Maybe she had to buy herself something, or maybe she didn't bother.
He goes up to his room and grabs his phone, acting on an impulse.
Merry Christmas, he texts her.
His mother calls him back downstairs since it's family time and he's expected to be there. He doesn't return to his room until late afternoon, carrying an armful of presents and ready to settle down with one of his new games for a long evening of doing nothing at all. Across the hall Mabel's door is open and he can see her spreading pictures out on every available square inch of her floor. He figures the next time he goes into her room he'll be walking into a virtual tour of the Shack. She probably won't have a single centimeter of empty wall left.
He doesn't remember to check his phone until bedtime. He's just pulling on his sleeping shirt when the reflection of his ceiling fan light catches the screen, gaining his attention. He grabs the phone and unlocks it. He has one unread message.
Pacifica: Merry Christmas
It's not much, but he thinks it means she's okay.
For whatever reason, he sleeps a little better that night.