AN: I don't own Gravity Falls. If I did, it wouldn't be nearly as extraordinary.
Dipper was tired. It had been a long day, what with switching bodies with his twin sister and all. They had been arguing over the new room at the shack and eventually Mabel had let Dipper have it. But not before they got to spend some time in each other's shoes, literally.
However, in the end, Dipper had found himself up again in the attic, after realizing that he missed it up there too much to stay in his new room. The next day he would be giving it to Soos to replace his crappy break room, but right then he was in a sleeping bag (He'd need to move his bed back) on the floor. Mabel had seemed to miss him too; his detective's instincts unnecessary in reading the relief and happiness on her face as she invited him in.
Reflecting on the day in the overly detailed way only Dipper seemed to be able to achieve, Mabel seemed to give up really easily once he explained his motives. Almost too easily, knowing how competitive Mabel usually was. And what was all that about being awkward and sweaty? She wasn't even in his body all that long. I wonder what she did as me, thought Dipper. Well other than trying to sabotage me. And why did Grunkle Stan just give 'Dipper' the key? I'll have to ask her.
"Hey Mabel," Dipper started, "Can I ask you a question?"
"Sure!" Mabel replied, "You can ask me anything!" Mabel was always enthusiastic. It was late at night, they had a long day, and yet Mabel still was able to add an exclamation point to the end of her sentence. It's kinda impressive, Dipper mused, how much energy she always seems to have.
"What did you do while you were in my body?"
Mabel's smile quickly faded and she barely suppressed a shudder as she remembered her talk with Grunke Stan earlier today.
Dipper, of course, noticed, and the hesitant silence coming from Mabel's half of the room was enough to let him know that something was amiss.
"Mabel?" he asked tentatively.
His twin seemed to snap back into reality. "What?" she asked befuddled. She remembered what Dipper had asked her and quickly added, "Yeah right. That…"
"Mabel? Are you okay? What's going on?" Dipper was really confused now.
"Mabel…" Mabel started nervously fidgeting under her brother's gaze.
Sensing Mabel's uneasiness, Dipper walked across the room and sat on the edge of her bed.
"Come on, Mabes," he said, starting to rub her back. "You can tell me anything."
"G-Grunkle Stan gave me The Talk today. He thought I was you and told me about the birds and the bees. He also suggested deodorant," she added with a nervous laugh.
And I thought the teen vampires were bad… Dipper thought. Mabel must be scarred, getting that talk from Grunkle Stan. Not to mention she had to have a man-to–man version.
"Oh Mabel," he started, "I'm so sorry. This is all my fault and…"
"You're sorry?" Mabel asked, incredulous. "I thought hearing about all that sweat and hormone-y stuff was bad. You're the one living with it!"
Dipper gave a slight chuckle at this. "True. But you shouldn't have had to hear that. If only I had just let you have the room then none of the body changing would've ever happened. I'm sorry."
"I'm sorry too," Mabel apologized. "I let the competition get the better of me. Why do I always do that? Am I always that immature?" Mabel had been questioning herself ever since she slipped into bed that night.
"What?!" Dipper asked, finding it surreal that Mabel would even question her maturity.
"Ya know? Boy crazy. Super competitive. Gets excited over stupid stuff and has no sense of who or who not to trust?"
"Mabel, why would you question your maturity? Sure you're a little silly. And maybe a bit too trusting. But that's good. That makes you you. Don't change just because you might've taken our competition a little too extremely."
"Okay. Thanks. Besides, I probably wouldn't be able to change if I wanted to- which I don't –being serious is hard. Do you remember Quentin Trembly?"
"Yes, yes I do," Dipper reminisced. "So, we cool?" he asked, holding out a fist.
Mabel completed the fist bump. "We're cool."