Happy end of finals week everybody! :D :D :D This was written and posted in celebration!

Takes place a summer or two after the series. Long enough for puberty to work its magic. Not canon to my other story, scrapbook-ortunities, or to anything else ever. Biologically inaccurate, or so I pray to God.

Warning: Poop, blood, and hormones. All that good stuff. :)

June

"What's the matter with you?" Wendy asks, glancing up from her magazine as a rather ashen faced Dipper collapses into a chair beside the front desk, clutching his middle. "You look like you got hit with a truck."

"It's nothing," he mutters unconvincingly. "Just- my stomach hurts."

Wendy nods knowingly. "Stan's been dumpster-diving for produce again, huh?"

"No, I think- he's been what?" Dipper doesn't even want to go there. "No, I thought it was something I ate, but it's been two days and it's just getting worse. It's like, cramping." He winces, wrapping his arms tighter around himself.

Wendy's eyes flit back to the magazine. "Eat some celery or something. You're probably constipated."

Dipper flushes. "I-"

"Dude, my grandma can make you a mean bean burrito that'll cure that right out of you." Soos drags the broom across the floor in an unsettling motion. "And I mean right out."

"Pooping is the cure for everything. Friend drama? Take a dump. Existential crisis? Plop. Negativity expelled. Problem solved. I'm gonna patent a drug that makes you poop out cancer, and save the world," Wendy says.

"Good plan," Soos tells his co-worker.

Wendy spreads her arms wide with her unfolding vision. "And I'm gonna call it the Miraculous Turd-tastic Wonder -"

"I pooped this morning, okay?" Dipper bursts out, too irritated to remember to be mortally embarrassed.

"Me too! Up top!" Wendy high-fives a bewildered-looking Dipper. "See, everybody does it, no shame." She was going to chill this kid out if it was the last thing she ever did, God as her witness. "Well, now we've just gotta rule out Ebola."

"Hey, Wendy?" Mabel whispers from the entryway to the Shack gift shop. "Could you come here for a second? Just you! No boys!" She gives them a death look. Wendy obliges, noting the greenish tinge to Mabel's face.

"For real, though, what has Stan been feeding you guys?" She puts her wrist to Mabel's forehead to check for fever. For the first time she's genuinely concerned. Dipper's the sort of kid to give himself a stomachache just by worrying about getting a stomachache. Mabel is not.

"I started," Mabel hisses. "And I've only had it like once, so I didn't remember to bring anything from home."

"Oh, man, that sucks. I got you, kiddo." Wendy walks into the bathroom. Mabel follows, breathing a huge sigh of relief.

"I'm so glad you're still here. I thought I was gonna have to tell Grunkle Stan." She and Wendy both shiver in abject horror.

"No way. Here, let me show you a little trick for future reference." Wendy taps on the medicine cabinet over the toilet twice, lightly, then gives it a hard knock, and Mabel watches, wide-eyed, as a panel in the side slides out to reveal a box of absorbent pads. "Ska-doosh. Soos knows every nook and cranny of this place, but even he hasn't found the secret stash. There's chocolate wedged in the back for extreme emergencies, too.

"You're a goddess," Mabel says.

"Let me know if you need anything else." Wendy walks back through the gift shop doorway, glancing back across the room at Dipper, who has face planted on the desk, clutching his gut and whimpering.

Nah. Coincidence.

July

They're having a Mystery Shack 'company picnic' on the green hillside, watching the clouds float in the sultry sky overhead. Mabel holds her sparkly purse full of necessities closer to her chest than usual. Dipper picks at his food halfheartedly, wincing.

"Grunkle Stan, I… I think I need to go to the doctor." Dipper sets down his sandwich. "It hurts a lot, and it's freaking me out."

Stan frowns, considering this. "Kid, I don't want to hear about your creepy intestinal parasites, so what makes you think some rich, snobby doctor does?"

"I just can't figure out what's going on. It happened last month when we first got here. And then maybe a month before that. Oh my gosh, it's a pattern." Dipper suddenly hops to his feet and starts pacing.

Wendy and Mabel exchange an alarmed look around their respective sandwiches.

"I didn't see it before but- Oh no. Oh my gosh no." Dipper digs what appears to be a miniature calendar out of his vest pocket and gestures to it wildly. "I- I keep finding blood in the trash. Have you noticed that, Soos?"

Mabel slowly pulls her head down into the oversized folds of her turtleneck.

Soos nods solemnly. "I assumed you had just cut yourself shaving and then narrowly avoided bleeding to death. Happens to me all the time."

"But I don't shave, Soos! The cycle… It lines up with the full moon. Guys… I- I think I'm a werewolf."

Mabel chokes on her soda. Wendy slaps a hand over her mouth and barely suppresses laughter.

"What about this is funny?" Dipper asks, obviously wounded.

Wendy asks Mabel with her eyes if she can tell. She's starting to feel terribly guilty, despite her giggle fits. Mabel shakes her head wildly, flushing.

So instead Wendy says, "Chill out, dude. You of all people should know not to jump to conclusions without all the evidence."

"You're right. Sorry." Dipper tries to take a deep breath, but something in his chest hitches. "I just feel sort of emotional right now," he admits, fanning his face with his hand to try to dry tears that have welled up out of nowhere.

They feel terrible about it later, really, they do, but Wendy and Mabel can't really hear their consciences over the sound of their uproarious laughter.

August

"Why you don't just take some Tylonel? It'll make you feel better, dum-dum." Mabel unwraps her emergency kit chocolate bar as she walks into the living room.

"Because I am very deeply in denial that this is happening to me!" Dipper snaps, doubled over in Stan's chair with a pillow pressed to his abdomen. He tries to steady his breathing, because the pain is only an illusion, everything he knows about science tells him this isn't possible, but dang it, they are in Gravity Falls and possible has never freaking mattered before.

"Well, you're the one who always wanted us to have twin telepathy, bro-bro!" Mabel is relieved that she doesn't have to suffer alone and in silence anymore, but another part of her longs to claim exclusive rights to monthly pain and irritability.

"You know, Dipwad, if anybody ever finds out about this, we'll be taken away by the government for top secret experimentation on our minds. Then you'll get to see inside Area 51 and all your lame nerd dreams will have finally come true. So why don't you count your blessings?" She cracks the chocolate bar in half and crams several squares into her mouth.

Dipper makes a growling noise in the back of his throat. "This isn't fair!"

"Yeah, well, suck it up, buttercup!" Mabel yells back, line-driving a chunk of candy at Dipper's head. "You wanna talk fair, man? At least you aren't the one bleeding out your-"

Dipper cuts her off by screaming into the pillow, longing for the sweet release of death.

Right after he stuffs his face with his half of the chocolate bar, that is.

This lovely bit of literature was based on a comment left on an article I read about twin telepathy. A teenage male twin claimed to have cramps whenever his sister was on her period. As far as I understand biology this isn't a thing, but on the other hand, why would he make something like that up? Maybe it's psychosomatic. ;) Hopefully. Sorry, Dipper.