Losing My Virginity to My Centaur Husband

It hadn't been her choice to be the one picked to be wed off to the centaur tribe to end the war between them, and she'd surely never have chosen herself. But would anyone? She could think of a few women who might have, the ones who she thought were a bit too handsy with the horses, with the cattle, but she'd never been one of them. And maybe they were better off for them, because surely they'd have only worsened relations by treating their new husband like a common horse.
That would have surely turned the tension to proper war.
And if she kept staring at his cock Alonis might grow offended and go to his chieftain. Then they might end up going to war because she was too cowardly to fuck her new husband. 'You gave us a defective maiden!' they'd say, and then people would die for it.
"Relax." The stallion's voice startled her, gaze snapping to him and he grinned, all dull teeth excepting his alarmingly sharp canines that gleamed in the dark. "It's not going to eat you, just explore it… get familiar with it."
He shuffled along the ground on his back like a horse trying to scratch an itch, hooking his arms over a log and propping himself up to watch her. Being watched was disconcerting but she'd never been a coward, so she shuffled forward and reached out, ghosting her fingers over his erection. It bobbed, dribbling, and she forced herself not to flinch.
"Easy," he rumbled like she was the one part horse. She set her jaw and reached out, taking it in hand and basking in the way he gasped, groaning, though when she realized her thumb and pinky couldn't meet around his cock even stretched out as far as they could go the color went from her face.
How is this going to fit inside of me?