While Mabel was in her bed, sleeping soundly, Dipper was still wide awake, thinking about the twins' day together.

They had spent the entire day wandering through the forest and looking for something new and excited. Unfortunately, everything they saw, they had seen before. Gravity Falls seemed to get less and less mysterious every year, it seemed. However, that didn't stop the twins from joking around, taking pictures and just plain enjoying the view and each others company. It was a fun day for both of them.

Except this time, it was different. At least for Dipper.

Instead of focusing on monsters and anomalies, Dipper was focused on Mabel. Her jokes seemed funnier, she seemed more fun that usual and he actually saw her as beautiful for the first time. Not that she wasn't attractive to him before, but now it was emphasized, so much that he couldn't ignore it. The way her hair glowed in the sunshine, her cute-as-a-button nose, her beautiful eyes...

Argh! God dammit, Dipper! Dipper thought angrily. What's wrong with you, man?

He couldn't figure out how he went to sleep that night. All he knew is that Mabel never left his mind.

Dipper groaned as he felt someone (or something) painfully squeezed his nose. He cracked his eyes open far enough to see Mabel, her face barely seeable through the darkness of the very early morning.

"Mabel?" He squinted.

"Yep." She confirmed, her voice lacking her usual energy. Dipper came to the conclusion that she was still sleepy.

Dipper rubbed his eyes. "What is it?"

Mabel's left hand rubbed her bare opposite shoulder. It was then that Dipper realized that she was only wearing a bra and panties. It wasn't unusual for her to wear that. He knew that it was what she slept in. But the fact that she wore the same ones she wore during their previous awkward events made Dipper's face turn red. Lucky for him, it was very difficult to see it in the dark.

"Sorry for bugging you at..." Mabel paused to check her phone for the time. "...1 in the morning, but... I've been thinking about something all day and I need to get it off my chest." The look on her face gave away that she was nervous.

Mabel could barely see it, but Dipper smiled anyway. It was both a happy and sad smile. Happy because he loved that his sister decided to talk to him over anyone else. He loved that she could count on him, the way he counted on her. It was also sad because something was really bothering her. He could see it in her eyes.

"Sure, Mabel. What's up?"

She began playing with her hair. "I... don't know how I'm gonna say this. It's really embarassing." Not even the dark could hide Mabel's crimson red blush. "You promise you won't judge me?"

Dipper shook his head. "Don't worry." He assured her. "No matter how weird or stupid or even illegal it is, I'll understand."

Mabel smiled. "Thanks, bro." She paused, staring into his eyes as she tried to gather up her courage.

"I-I..." Suddenly, she stopped and hung her head. "I-I can't say it. I'm sorry for waking you up. Goodnight." She said plainly, standing up from the edge of Dipper's and began to walk back to her own. But halfway there, she stopped.

"Wait." Mabel said, without turning around.

"Yes?" Dipper, who hadn't moved since he was woken up, watched her as she turned around slowly. Why is she acting this way? He wondered.

Mabel slowly walked to the head of Dipper's bed, where he lied, her steps full of hesitation. She stopped at the very edge and leaned over him, her face only mere inches from his.

There was a few seconds of silence. Dipper's eyes were locked onto Mabel's and vice versa. Neither of them moved. Then suddenly, Mabel closed her eyes and began to lean in.

"Mabel?" Dipper said, but she didn't seem to hear him, as she continued to get closer. Three inches apart, then two, then one and then he felt her lips touch his. The kiss was only intended to be for a split second, but in that time, Dipper felt something ignite inside of him. Before he even knew what he was doing, he wrapped his arms around her and pulled her in tighter.

In the back of his mind, Dipper knew that he shouldn't be doing this. He knew it was wrong, forbidden, taboo. But he couldn't bring himself to stop.

Is this how I feel about her? He wondered as he began to run his fingers through his twin's hair, loving the way the little soft curls felt.

To Dipper's surprise, Mabel suddenly began licking at his lips, wanting entrance to his mouth. He had never used tongue in a kiss before. Hell, until about a minute earlier, he had never been kissed on the lips. But he opened his mouth anyway, granting access to it.

The twins began exploring the other's mouths, their tongues dancing wildly with each other. This pushed Dipper to become bolder, sliding one hand from her hair to further down, feeling the smooth skin on her partially bare back.

He began to feel something rising in his crotch and rising fast. That's when he realized that at some point, Mabel had positioned herself so that she sat directly on his crotch.

They pushed even further, deepening their kiss and making their tongues explore every part of their mouths. Mabel began to copycat her brother, putting one hand firmly in his hair and the other slid under his shirt, feeling the bare back of her twin.

Both twins gasped as Mabel experimented rocking her hips slightly against his. Feeling both of their crotch areas against each other gave them a feeling that neither of them could get masturbating. The new sensation pushed Dipper into overdrive, breaking the kiss to reach for the back of his sister's bra, trying to undo it but finding himself unsuccessful.

But as he fumbled with the piece of underwear, a realization hit him. He retracted his hands from his twin and stopped moving his hips. This broke their grinding rhythm, causing Mabel to stop as well.

"Dipper? What's the matter?" She asked. It was too dark to see, but her brother still could imagine the almost-hurt look on her face.

"What's the matter!?" Dipper repeated. "Mabel, you're my twin, for god's sake! We shouldn't even be thinking about doing this, letting alone actually doing this!"

For a few seconds a pause filled the air until Mabel spoke up. "But-"

Dipper cut her off. "No. This has to stop, right now, before this get out of hand. Okay?"

Another pause this time, way longer than the first. However, Dipper didn't expect to have Mabel wrap her arms around him, locking him into a hug. He also didn't expect for her to start crying while her head was buried in his shoulder.

"You're right." She finally said through her tears. "I'm sorry. I didn't know what I was thinking. I'm so, so sorry, Dipper."

Dipper just held her in his arms, letting Mabel cry as much as she wanted. She apologized over and over again. He just let her do whatever she needed at that time.

But after only a few minutes, she stopped. It wasn't until Dipper heard a snore that he knew she was asleep. Due to their long hunt, she was already exhausted and sleep-deprived, and had just fallen asleep in her brother's arms.

Quickly, but gently, Dipper picked his sister and walked over to her bed. He placed her on it. He watched for a minute before he covered her with a blanket. He then retreated to his own bed, his mind racing. Finally, he fell asleep, with one last thought on his mind.

We're going to fix this, Mabel. I don't know how, but somehow we're gonna fix this together.