Rated 13+

Dipper walked down the town of Gravity Falls, walking side by side with his sister. It was their annual 20th birthday. Mabel was so happy she didn't know what sweater to wear before they headed for the bus back to Gravity Falls.

"I can't wait what Candy and Grenda have planned for me!" Mabel exclaimed, getting hyper by the minute.

Dipper sighed and nudged his messenger bag higher over his shoulder. "Yeah..woo hoo..."

"You're not still sad that Wendy can't celebrate our birthday, are you?" asked Mabel as they took their final steps onto the Mystery Shack's porch.

Dipper began to blush and shook his sweating hands. "N-No! I said I'm over Wendy!"

Mabel rolled her eyes, letting her dangling braid flow in the wind. However Dipper rolled his eyes back at her and turned the door knob, allowing both of them in.

Every tourist in the shack looked at them and smiled. "Happy Birthday!"

Even Grunkle Stan rolled in on a wheel chair with a toothless smile. "H-Happy Birthday..," he wheezed.

Mabel covered her mouth and gasped. "THANK YOU!"

Dipper sighed and hung his head down. He shamefully tucked his hat on the cashier. Stupid Mabel. She always gets all the attention...even all the attention from Stan. He headed upstairs to his room and shut the door quietly, hearing everyone cheering Mabel's name from downstairs. He frowned and threw his bag onto his rickety bed, planting himself on the edge of the mattress. He looked through the wooden cracks of the ceiling and leaned back.

"Hey there, Pinetree!" a voice said cheerfully as Bill's human face looked at down at Dipper's.

Dipper threw himself up and nearly tripped off the bed. He looked at Bill with a startled look. "Y-You idiot!" he insulted. "Y-You scared the he-hell out of me!"

Bill laughed amusingly and pulled out a pinetree-shaped cake from his back. Candles emerged onto the icing surface, spelling out Dipper's name.

"Finally you know my name," Dipper joked and wiped his forehead, wiping the sweat off onto his jeans.

"I heard it was your birthday!" the demon exclaimed once more and hung upside down. He handed the cake to Dipper who quickly set the cake down onto his desk.

"Uh..thanks!" Dipper said. He sat on the brim of the desk and shuffled his socks against the rusty wood. "But why celebrate my birthday?"

Bill adjusted upright again and spun around slowly, the tails of his golden, silky coat dragging along the floor. "Well I realized you don't get much attention on your birthday except your sister and that red headed cashier girl."

Dipper blushed awkwardly. "It's only girls of my age who actually greet me a happy birthday...and then they do this fan girl squeak and run off as if I was a superstar..."

Bill made a delighted cackle of sorts. "Really? Girls only, huh?" He drifted over to Dipper and rubbed his hair while the brown strands flung away from the smooth set curves.

Dipper swiped at Bill's hand and swept his hair back, fixing it quickly. "Yup," he answered and leaned back against the desk, craning his neck around to gaze out the window sill. Gently he felt soft, silky gloves pile his bare hands as he looked at that one, mischievous eye.

"Don't you worry..Dipper," Bill purred and ran his glove along Dipper's jacket, grazing his teeth demonically over the younger man's lips.

Let's get this understandable. Bill is 21, and Dipper has just turned 20...but Bill's birthday is unknown.

"Uh-Uh...," Dipper said nervously. He clutched Bill's tailcoat and tried to push the older man away, but Bill remained in the spot, barely budging. Only his chest moved, and his arms...and his lovely eye.

"What is it, Pines?" said Bill. He curled his fingers into the empty gaps of Dipper's fingers, clutching the young adult close to him.

"B-But Bill!" Dipper whined. "Wh-What if Mabel comes in here!"

Bill smirked wickedly and threw his hand out, the door locking by his movement's orders. "Wish granted," he purred once more as he began to blush, an erection beginning to fill his underwear.

Dipper gulped, feeling the lump slide down his dry throat. It rattled back up, sending a whisper of trouble. The boy aggressively wrestled Bill out of his way and headed for the door. "I thank you for the cake and the gift, bu-but I have to go-!"

Bill swung Dipper against the door, pinning the struggling man with a demonic smirk. "Oh, Dipper," he said and tilted Dipper's chin up. "I still have more gifts to give you..." The human dream demon smashed his lips hungrily against Dipper's, immediately forcing his tongue into Dipper's exposed mouth.

Dipper blushed and moaned for the first time as Bill's tongue struck for his. Saliva edged out of his mouth, their lips making a sweet sound as Bill pulled away. His eyes closed halfway as he looked down at his socks, blushing miserably.

"I know you loved it, Pinetree," Bill whispered. "I'm a mind reader, remember~?"

Dipper stunningly widened his eyes, blushing past his limits. "I-I uh...um..." Damn it, Bill...you idiotic prevert!

"I'm afraid I'm not a pervert," Bill sang tauntingly.

F-Fuck you! Dipper cursed.

"Fuck you?" Bill echoed. "I'd be glad to, Pines..."

"W-Wait! No!" Dipper yelled and wrestled with the demon again.

Bill laughed at Dipper's attempts and gently tilted Dipper's chin higher, now seeing Dipper's neck. "Uh-oh," Bill said, smirking wider. "Some cake icing got on your neck..." He gently placed his tongue on Dipper's soft skin, licking up the icing.

Dipper struggled and moaned, shuddering with every wet movement of his tongue.

"Enjoying your gift, Dipper?" Bill said, pulling away from his neck.

F-Fuck...m-me... Dipper thought, purposely for Bill.

Bill's eye seemed to gleam in a surprised expression. "R-Really?" he said, blown away. "A-Are you sure?"

Dipper looked hazily at Bill, blushing at him. "E-Eh...I didn't think that..!" he joked awfully bad, beginning to struggle away again.

"You're not going anywhere," said Bill as he pinned the boy against the bed again, making sure the man didn't struggle as much.

Dipper bared his teeth dangerously at him and swung his legs around. "Let me go you jerk-!"

Once again Bill stubbornly kissed Dipper again as Dipper submissively allowed the demon to do what he liked.

After all...it is his birthday...