Dipper frowned as he watched his illuminati boyfriend strut around on the whiteboard. Of course nobody else in his class could see the pregnant yellow triangle flirt with the math problems, but that didn't make things any easier for Dipper.
During the summer, Dipper had accidentally gotten Bill Cipher pregnant, and ever since then Bill hasn't given Dipper a moment's peace. Not that Dipper minded. Dipper loved the fact that Bill was more cuddly and affectionate, but that was before he had to go to school.
Throughout school hours, Bill had made it his personal mission to get Dipper in as much trouble as possible, he'd pretend to be triangles in math problems, walk around in human form –while invisible- copying all the movements of the teacher, whisper things Dipper tried not to think about at school into Dipper's ear, sit on people's heads and make faces, and draw things on the board while no one was looking. Dipper hadn't cracked yet, but that only made Bill even more determined.
Mabel –who was sitting next to him- noticed Dipper's expression and quickly ripped off a corner of her page and handed it to Dipper. Seeing this, Dipper sighed in relief and drew a triangle on it and tapping each edge of it three times. It worked a bit like the usual summoning ritual; calling Bill over and trapping him on the page where the triangle was until a part of the triangle was removed. Dipper would have always kept Bill in it if it weren't for the fact that it made Bill very moody, and Dipper would get scolded afterwards.
Bill began to yell –now that he was attached to a physical object, he could be heard by normal people- but Dipper responded by covering him with his maths book.
Dipper let Bill out during the lunch break, and Bill decided to let his powers relax so he took a human form and made himself visible.
"Why are you a girl?" Dipper asked, patting Bill's baby bump as he hugged Bill from behind.
"I figured it would make more sense to your human friends if they saw a pregnant girl instead of a pregnant boy" Bill shrugged; his voice had changed a little too.
"I thought you were out to drive me crazy" Dipper chuckled, resting his head on Bill's shoulder.
"Only when you can't talk to me" Bill replied, enjoying the hug.
He suits being a girl, Dipper thought, admiring Bill's knee length gold hair and curved hips.
"Are you saying that you'd be more affectionate with me if I'm in this form?" Bill questioned, Dipper couldn't tell what Bill though of that idea.
"…Ah, you can read thoughts" Dipper facepalmed.
Bill giggled.
"Okay, yeah, I would be more affectionate, but that's because ever since you got pregnant you've been acting more and more like a girl" Dipper replied, "it confuses me sometimes."
"I guess I could stay in this form for you, Pine Tree" Bill smiled.
"So that's a…good sign?" Dipper guessed, knowing Bill could do a complete 180 in seconds.
"Yup!" Bill grinned, "now come on! I wanna meet your friends properly!"
"Hey, wait, what would I call you?" Dipper asked, "should I call you my girlfriend –wow that's weird-? And your name? Bill isn't exactly a girl's name."
"Call me Nina" Bill told him before dragging Dipper off to his table where he meets his friends each break.
Dipper's friends laughed when they noticed him being dragged to them by a girl.
"Who's this?" One of Dipper's friends wondered, his name was Luke.
"My…girlfriend" Dipper blushed, unconsciously rubbing Bill's swollen stomach by habit.
"…Whoa!" All four of Dipper's friends gawked when they noticed that Bill was pregnant –hard not to notice when Bill was half way through his pregnancy-.
"H-She really wanted to meet you" Dipper continued.
"Is the kid yours?" another one of Dipper's friends, Brian, asked.
"Of course it's mine, what, do you think he- she's some kind of whore?" Dipper growled.
Bill laughed a little.
"JUST CURIOUS!" Brian squeaked, causing Bill to laugh even more.
"Hey Dipper, who's thi-" Mabel had come to see what the commotion was about, and she only just recognized Bill half way through her sentence, "oh sorry, it's you…uh…"
"Nina" Dipper whispered to his sister.
"Nina, right, sorry. I always manage to forget your name" Mabel laughed nervously.
"So, Dipper," the third one of Dipper's friends, Mike, spoke, "why didn't you tell us about your girlfriend?"
Dipper twitched, he didn't know how, but Mike had the ability to see through lies, like a human lie detector. Dipper thought Mike wouldn't be able to see through a lie like this one though.
"Why don't you tell us how you met her" Mike continued. Yup. He'd picked up on the fact that 'Nina' wasn't actually a girl.
Bill knew he was busted too, which only amused him.
"Alright, come on" Bill instructed.
"Huh?" Dipper's friends blinked.
"What's going on?" Mabel wondered.
"I just wanted to mess with them anyways" Bill laughed, confusing them more. Mike had some idea of what was going on, but it still confused him.
Bill led the group –which had doubled thanks to Mabel's curious friends tagging along- around to the back of the school where no students were, and, without a word, Bill changed to his usual male form.
"…" No one said anything. Dipper just sighed and facepalmed while Mabel giggled a little.
A few minutes later, Dipper realized that his friends have gone mute.
"So, this is Bill" Dipper reluctantly explained, "he's a demon."
"He used to be our enemy, but now he's Dipper's boyfriend" Mabel continued, feeling that her brother needed a little support.
"And yes, I'm actually pregnant and Dipper is the father" Bill grinned, trying not to laugh, "we're having a little girl in six months!"
Dipper scowled at his boyfriend, wondering why he even needed to show himself in the first place.
Finally, one of Dipper's friends spoke, it was the smallest of the group, and he rarely spoke at all, "what happens during your summers?"