For the character Dusk Shine (R63 Twilight Sparkle). A spell goes horribly wrong and now every time anyone says a certain word he has an orgasm.

Don’t say it, Dusk chanted to himself. Don’t say it, don’t say it, don’t -

“ - so I thought we might go to that new magic show later.”

Before he even had the chance to think fuck, Dusk Shine felt his hindbody tense up, flex, and suddenly thrust downward. He moaned as his orgasm swept through him without a single note of warning, his stallionhood seizing up and spraying out rope after rope of thick, white cum all over the floor.

“What - “ Elusive paused and blinked at Dusk - or rather, at Dusk’s mess. “My goodness. Er. Dusk, my dear - should I leave you alone for a bit?”

“Nggh,” Dusk grunted, still pulling himself back together as the wave of pleasure receded from his body, leaving behind only a burning in his cheeks. He could still feel the cum dripping down to the carper, could feel his still-erect stallionhood slapping up against his belly as his balls slowly swelled up again. “I - no. Gosh, no. Elusive, I’m so sorry.”

“Don’t…be?” Elusive raised an eyebrow, his eyes very obviously avoiding Dusk’s dripping shaft. “Is something wrong, then? If you don’t want to, we can still go to the magic - ”

Dusk let out a cry, his hips thrusting forward so hard that he felt his hindlegs buckle under him. He collapsed to the ground, biting his lips and breathing quickly as his balls emptied right beside the puddle of spooge he’d just left.

“Don’t,” he huffed, feeling the sticky puddle spreading out beneath him, “say…the word. Spell…gone wrong.”

“Oh, my stars.” Elusive quickly helped Dusk to his hooves. “I’m so sorry. I didn’t know. If you don’t want to go to the ma -” - he caught himself, a hoof flying to his muzzle before he smiled sheepishly - “to the, well, show, then I wouldn’t blame you.”

“But everypony else will be there.” Dusk took a deep breath. “I don’t want to be the only one who isn’t going. I can handle it.”

Elusive frowned slightly. “Well. If you’re sure.”

___________________________________________

“Welcome, everypony, to the magic show of the great, magical, and all-powerful Trevor!”

Dusk shook slightly as fireworks went off above the cart. He was biting his lip as hard as he could, struggling to stay still as two orgasms rode through him at quick succession. He could only be grateful that everypony else’s eyes seemed to be directed at the stage, rather than at the extended stallionhood between his legs, or the growing puddle of cum beneath it. He’d already cum seven times now, and was beginning to think that coming out here had been a bad idea. How the hay had Bubble Berry managed to use the word three times in a single subordinate clause?

“Behold! A magical feat for the ages!”

This time, Dusk couldn’t hold in his low moan as his cock throbbed and spurted, leaving a thick rope of cum still hanging from his cockslit. He could already feel his balls refilling, churning and sloshing with cum just waiting for the right word to set it free.

Maybe he should head back home after all.

“No mere unicorn could perform magic of that caliber!”

Ohh - fuck. That one felt even better than the last twelve combined. Dusk Shine bit his lip and glanced around, his hoof slowly going toward his underbelly. Maybe he could stand to stick around a little longer…