Macro Pinkie grows every time she has an orgasm. Equestria might try to stop her, until it turns out her marecum is addictive.

Pinkie shuddered with pleasure as the orgasm swept through her, her marecum spilling out over the bed. And this time, the bed shattered beneath her.

She moaned happily. “Oh, Gummy,” she said, Gummy himself stuck somewhere beneath her massive flank. “You have no clue how absolutely amazing this feels!”

Her hoof didn’t budge from her clit, which was now dripping in greater volume than ever before. Pinkie kept panting, kept rubbing as fast as she could, her entire body seeming to vibrate as it finished expanding.

Her body arched back again, and she let out a second cry. The floor beneath her growing flank creaked loudly as her head shot up toward the ceiling, her growing nethers exploding with marecum and her wide-spread legs stretching toward the sides of the room.

“So…good,” Pinkie said, panting.

“Pinkie!” The door slammed open, and Twilight Sparkle burst in through the door. Her eyes opened wide, and she backed up a few paces from the enormous pink pony. “Sweet Celestia, I knew I shouldn’t have given you that spell!”

“Mmff.” Pinkie’s eyes closed, and she bit her lip. “Mm…Twilight. I’m so…big…”

“Yes,” Twilight said. She took off from the floor and hovered next to Pinkie’s enormous face, her wings flapping slowly. “And that’s a problem! We need to get you back down to normal before you crush the bakery!”

Pinkie shuddered, her entire body shooting up a few inches. “Oh…but I’d love to be so big. Big enough to spread my fun all over Equestria. Mmff….” Her hoof kept rubbing her clit, and she began to hump the empty air.

“Pinkie, I need you to stop. I need you to - “

With a third and final cry, Pinkie came once again. Marecum splattered out all over the walls and ceiling, juices leaking and dripping over everything in sight - including Twilight, who stopped midword.

A single drop fell into Twilight’s open mouth, and her entire body shuddered.

When Pinkie came to, the sun was shining down on her, and the crushed remains of Sugar Cube Corner lay shattered beneath her block-sized flank. She heard a slurping from far below. When she looked down, she saw Twilight herself, eating out Pinkie’s preposterously-sized pussy as fast as she can. From what Pinkie could see, Twilight’s stomach had even started to sag from the amount of marecum she’d devoured - and Pinkie still felt ready for another go.

“Oh, yes, Twilight,” she moaned, envisioning herself growing to overshadow all of Equestria. “Just…like…that.”