"So, you know," Yamato says, taking another hit of the blunt before passing it to Taichi, "the multi-universe theory?"

The two men are lying on Yamato's bed, the late afternoon sun peaking through his window, making patterns on his floor through the curtains.

Taichi's brow furrows as he exhales, rounding his lips to create smoke ringlets. "What, you mean the one that you're always going on about?"

Yamato snorts, his eyes following the rings as they expand and disperse into the ceiling.

The room is bare save the bed, desk, guitar, and countless books and academic journals stacked on top of each other along the walls. Yamato moved into his new place a few months ago and still hasn't had time to do anything with the space. It's something his younger self would probably disapprove of, because regardless of how messy his childhood apartment had been, or how disgusting the dorm he lived in during his undergraduate degree was, they at least had a certain character.

"Yea, the theory of multiple universes. You'd think someone with your history would have at least a rudimentary grasp on the subject," Yamato scoffs, grabbing the shortening joint out of his best friend's fingers, to the protest of said best friend. He props himself up on his forearm, and takes a drag, raising an eyebrow to Taichi's scowl.

In response, the brunet raises his arms above his heads and stretches languidly in a cat-like manor that Yamato sometimes teases him for.

"I'm not the one doing my PhD in physics here, but I don't think the Digital World can be explained by the concept of infinite and constantly diverging parallel universes. It's another beast entirely," he says as he drops his arms back to his sides, fingers scratching at his belly.

"Ah, so you do listen sometimes," Yamato smiles and puts the blunt into Taichi's mouth, fingers brushing against his perpetually chapped lips. "And it's extragalactic astrophysics. I'm sure those assholes in biophysics wouldn't be too happy to hear you clumping us together in the same category."

Taichi's fingers brush against Yamato's as he takes the joint, trying to ignore to jolt in his stomach at the contact. "Your nerd feuds are so sexy. It's like a South American soap opera combined with an episode of the Big Bang Theory," he deadpans.

This game isn't exactly new, and Taichi is well used to it- all lingering touches and heated glances. Sometimes Taichi needs a roadmap to understand the things going through his best friend's head, but all of this feels like it's leading to something, one way or another, like they're climbing this hill together towards a very certain destination. How much longer will they have to climb? Taichi wonders sometimes, especially in moments like these.

"And whether it is another beast entirely is really up for debate. We don't know at this point," Yamato says, snapping Taichi out of his reverie and ignoring his last comment completely.

"Isn't Koushiro supposed to be the geek of the group?"

Yamato clicks his tongue and kicks Taichi in the shin. "You come to my house, smoke my pot, and what, throw insults at me in a display gratitude?" The blond's smile betrays his amusement.

Taichi mirrors the smile as he lunges up to wrap his arms around the other man.

"Aw, Yama, you know I love you the most, my grumpy little wolf!" He knocks Yamato flat on his back and rolls both of them over so that Yamato's face is smothered into the bedspread over Taichi's shoulder, their torsos pressed together snugly.

And again, Taichi is used to these moments, edging the acceptable limits of friendship, on the cusp of something more.

Miraculously, the joint survives the tumble and Taichi presses it to Yamato's lips, mirroring Yamato's earlier gesture, as the blond props himself up on his elbow. Yamato's lips are hot on Taichi's calloused fingers and spread the heat and vibration through his entire body as the blond takes a drag.

Taichi's breath hitches at the contact and he can't help but stare, transfixed, fingers lingering longer than necessary before putting the blunt to his own lips once more, closing his eyes to center himself.

"There's an extension to the theory." Yamato's voice is quiet, his body is radiating heat so close beside Taichi. It takes Taichi a minute to remember what they were talking about.

"Yea?" The brunet keeps his eyes closed, focusing on the in and out of his breath, on Yamato's voice so close to his ear.

"Yea," Yamato murmurs.

After a long pause, Taichi opens his eyes to find Yamato has closed his, pinky finger curling into his cheekbone as his hand props his head up. His lips are slightly parted and Taichi forces another steady inhale and exhale lest it break the atmosphere, all dreamlike and hazy and soft around the edges.

"It's called the many mind hypothesis or quantum mind, or whatever," Yamato continues after a while. "This theory says that it's not the universe that diverges, but our perspective. One brain, infinite minds."

"What does that mean, exactly?"

"It means that in your brain exists a consciousness that never went to the Digital World. Or one that has a little brother instead of a little sister."

"Oh, so that also means that there's a consciousness of you that is a world famous rock star instead of a studious PhD student?"

Yamato's blue eyes finally open and he catches Taichi looking at his lips. When their eyes finally meet, it's with an undercurrent of heat. "Just like there's one of you as a professional soccer player rather than a diplomat-to-be."

Yamato's free hand comes gently to Taichi's face to brush away a strand of hair on his forehead. Taichi's breath hitches again and his eyes move back down to Yamato's lips out of their own accord, joint out and forgotten in his hand. Yamato's fingers linger on his forehead, causing those same vibrations through his body.

There's a pause.

"So what you're saying," Taichi murmurs as he props himself up, "is that there's a corner in my mind where I've already kissed you." He stares into the abyss just beyond that hill.

The words are unplanned, entirely the product of the weed, Yamato's proximity, Yamato's fingers on his forehead, the heat in his eyes as well the years and years of buildup between them leading to this. If Taichi is to turn around now from this abyss, he would be able to see the years and years they both climbed to get this this point.

Yamato takes it in stride.

The hand on Taichi's forehead slides into his hair and Yamato, huffing out a quiet laugh, brings his face down to meet the brunet in a kiss.

The kiss is half sleepy, half hungry, with the latter taking over once Yamato pushes Taichi back down to the mattress and presses their chests together. Taichi can feel his own beating heart superimposed with Yamato's. He brings his fingers under the hem of Yamato's t-shirt and slides them up Yamato's naked back. Yamato moans into his mouth in response and Taichi tries not to lose himself entirely in the heat and haze of the moment.

"There's a part of my brain in which we have both spontaneously combusted," Yamato murmurs against Taichi's lips when they break for air. "There's a part of my brain in which a meteor hits this apartment building and we both die."

"Wow, all doom and gloom with you," Taichi murmurs, licking the line of Yamato's mouth. Yamato, in turn, sucks on the brunet's bottom lip as he moves to straddle him, both hands firmly gripping his hair.

Taichi uses this opportunity to roll both of them over so he lies between Yamato's legs. Taichi thinks that maybe some of these alternate minds have seeped into this one because when all of this should be unfamiliar, it is instead so comfortable: being pressed up against his best friend, panting against his lips, kissing his neck, brushing his thumbs against his ribs.

"It's a beautiful theory, though, isn't it?" Yamato, despite everything, continues. Taichi makes a rumbling noise into his neck as a response. "It links our consciousness to the universe in a such a beautifully significant way," he pants as Taichi continues to suck onto the juncture of his neck and shoulder, wrapping his legs around Taichi's hips to pull him closer.

All conversation ceases for a while, until Taichi pulls his mouth from Yamato's neck. "So how would someone even prove this theory?"

This question catches the blond off guard, his eyes unfocused and blinking slowly up at the brunet, and now he is the one that has to remember what they were talking about.

Then he rolls them over once more and grids his hips down to Taichi's, eliciting a breathy moan from the other man. Yamato leans down to bite on Taichi's earlobe.

The brunet's body moves of its own accord as his hips lift back up to replicate the contact.

"Well, there's no way to really prove it for now."

"For now?" Taichi breathes, eyes rolling back at the sensation of Yamato's tongue and teeth on his ear.

"Who knows what we'll be able to discover in the future. Maybe the universe is just stacked on an infinite number of turtles."

Despite the heat situation, this comment elicits a laugh from Taichi who then moves his head to capture Yamato's mouth in another searing kiss. He pushes himself up to sit, bringing Yamato along with him to sit on his lap.

"Should we talk about this?" he murmurs against Yamato's lips once the kiss slows.

"Isn't that my line, oh Bearer of Courage?" Yamato murmurs back, eyes still closed, still pressed against Taichi.

"Yea, but it's you, so…" the brunet trails off, opening his eyes to look at his best friend, who, in turn, also opens his eyes and waits for Taichi to continue. "So it's important."

Yamato smiles and kisses Taichi's temple. "We can talk about it tomorrow," he says.

"Okay."

"Or maybe in a parallel universe."

"Or in a different part of our consciousness? Or maybe those infinite turtles can delegate on our behalf"

Yamato snorts and pushes Taichi back down onto the mattress in their eternal power struggle. "I doubt that the turtles responsible for holding our universe in place would have time for that kind of thing," he says and takes his revenge on Taichi's neck.

END

Since Tri is coming out, this will probably be my last chance to post my post-series headcannons without them being ridiculously AU.
Though I never like to follow that whole everyone has a Digimon ending, I do like to explore just how each character got into their profession.

Having said that, I do feel like I'm just writing the same story for these two over and over again. Ah well.

All of the theories Yamato mentioned are out there. Sort of.