"It's the last day of school!" Dipper thought to himself as he struggled to pull himself out of his warm, cozy bed. Although it was the beginning of summer, and just the thought of leaving the house in anything more the shorts, and a t-shirt could make anyone sweat, the house was cold from air-conditioning.

Dipper, sitting on the end of his bed, opened his eyes, looked over at Mabel, peacefully sleeping, and lit up by a ray of morning sun. He put his feet on the fuzzy carpet, got up, and headed towards the bathroom. As he was walking out of the room, he thought about the two different sides of the room. He looked around and took it all in. His side, more dark and gloomy looking, full of posters of his favorite song artists and pictures of girls, wearing next to nothing. While on the other side of the room, bright and colorful, with unicorns and the newest boy bands.

Dipper then looked down at the ground and noticed a pair of white and black striped panties that belonged to Mable, on his side of the room. Furiously, he went to pick them up, as him and Mabel had the conversation about "the invisible line" many times before: both of them agreeing to keep one's belongings, on their side of the room, though, she continued to throw her clothes all over his side of the room. Ignoring the want to scream at her, he decided to simply unplug her alarm clock instead, as a last day of school joke. Then, going to set the panties on her head to make things worse, he noticed his hand feel a damp spot.

He looked down his hand and realized, it was right in the crotch zone of Mabel's panties. Being the panties she had worn the day before, the damp spot was cold, and some parts were a little hard. He examined the panties: the little white spot where her vagina entry would be, and a line of clear liquid, that went up as far as her slit would. Thinking about how he would love to feel the warm, wet feeling of a real vagina he felt the damp spots.

Snapping out of it, he set the panties down on Mabel's head, and shook off the thought, realizing they were his sister's panties. The thought would normally gross him out but this time, left him wanting more. Then he thought of how wrong it was to think like this, and headed off to the bathroom.

As dipper was brushing his teeth, with his blue and white toothbrush, he noticed that the toilet next to him was full of pee. He rinsed the toothpaste out of his mouth, the painful feeling of cold water shot through his teeth, but didn't bother him because he was mad. He stormed into the room, where Mable was still sound asleep, screaming.

"I thought I told you to flush the damn toilet after you use it, it grosses me out!" Dipper yelled.

Mable, looking at him with a look of daze and confusion from just waking up, responded with

"How many times have it told you, to put your clothes in the laundry"

"At least I keep my clothes on my side of the room"

"Well at least I don't look stupid"

" Well, at least I don't look like my pet" dipper said pointing over to waddles the pig, and letting out a laugh.

"Well thanks for calling me cute," Mabel said as they were both now laughing, realizing that their friendship was incredibly strong for siblings. Mabel looked up at Dipper standing there, with a gleaming ray of morning sun, making his bulge more obvious.

See, Mabel had been experiencing sexual feelings for Dipper for quite some time now, and these feelings drove her crazy: the thought of wanting him so bad, but thinking she will never get the chance, the feeling of excitement and nervousness when she spies on him getting changed. The bulge was making her blush, and feel a wave of excitement go throughout her body. She then noticed the panties sitting beside her head, realizing Dipper had put them there. She wondered if he had noticed the damp spot, that was caused by watching him get changed the night before.

"You ass, why did you put my underwear on my head?" Mabel said in confusion.

"Because you left them on my side of the room"

Dipper then got changed in the bathroom, went downstairs, and ate a big bowl, of his favorite cereal. "MABEL!" he yelled from the bottom of the hardwood stairs. "It's time for school!". Mabel then rushed down the stairs and they left to Catch the school bus.

Most mornings, Dipper and Mabel sat together, but this day, unlike many others, there was minimal people on the bus, allowing Dipper and Mable to sit alone. The bus was like any other school bus: yellow on the outside, gray on the inside, with an annoyed looking bus driver. The sound of the engine roared, and the sound of screaming children flooded the bus. Dipper stared out the window, and realized, he was sitting alone, not having to talk to anyone, he was able to think freely. He thought about the damp, white and black striped panties he found on the floor this morning. He thought about the wet spot, and wonder how it would feel if the wet spot was warm, and how it might have smelled, and how amazing it would be if he could feel a real dripping wet pussy. These thoughts released a warm, feeling throughout his body, and made him hard, with a sexual lust that was unlikely to be filled, not by anyone one but himself.

The day at school was just like any other, boring, long, tiring. The only difference being the excitement of going to gravity falls after school, seeing friends they hadn't seen since last summer, discovering new and mysterious things, the thought of sharing a room with one another, that would drive most sibling crazy, but Mabel and Dipper were used to this. in fact, the thought of sharing a room, made the twins feel happy. Mabel having the sexual feeling she's had for a while, and Dipper discovering his new sexual interest in his sister.

The bell rang, and the end of school was here, all the kids rushed out and the sound of excitement fled the hallways. Dipper and Mabel met up near the vending machines, the usual meeting spot for them, and headed for home, where they would finish packing and head for the bus that would take them to gravity falls.