A devious vibrator

The real surprise for Mackenzie came as the guard pulled her arms up and **** her to bend forward. "Hold her like this." said the head groom, and the redhead waited with her legs spread, shuddering as a cold speculum spread her labia. Gloved fingers entered her vagina and a small object was pushed in, sliding up until it got buried deeply inside her. Whatever the was, it pressed snugly against her cervix and caused her to moan loudly in the gag. "Hold a little more. Ok. This is perfect."

The guard stared curious, watching this process for the very first time. "What's that? Looks pretty complicated." "Not at all." The head groom went on to explain. "It's quite simple, actually. Let me turn it on first." Something made a faint chiming noise and Mackenzie felt a faint, yet noticeable movement deep inside her. Whatever was inserted into her began vibrating against her cervix, and soft tremors started radiating along the pelvis and throughout her body. "Watch this."

Mackenzie bucked nervously and stomped helplessly on her hulking boots as the vibrations intensified. Her teeth sank into the bit and her nostrils flared as she let out a heaving hiss. She tried to close her hand into a fist, but the binder's mittens wouldn't let her. She desperately curled her toes, but the boots were too snug. She tried to crouch, but the boots refused to let her - the only way she could bend her knees was if she lifted her feet, and the boots were incredibly heavy, so all she did was to strut in place helplessly.

Mackenzie was powerless, tightly bound into the pony suit that encased her, and could barely move around in her pony boots. The feeling of arousal kept growing and growing even after the vibrating sensation stopped increasing. The head groom and the guard watched quietly as she writhed and stomped for minutes until everything exploded, gripping her entire body into the most powerful orgasm she ever experienced. Her whole body quivered and her mind went blank for what seemed like an eternity, desperately trying to cling to the sensation.

"It's a vibrator attached directly against the cervix." The head groom explained simply as she turned down the dial, lowering the intensity of the vibrations. "We keep the ponies horny at all times. It makes them tame and extremely docile." The guard looked curious. "Why not a regular vibrator?" "For one thing, stimulating the cervix is more effective. And the orgasms are insanely strong. Isn't that true, honey?" Mackenzie nodded, involuntarily. "Well, that's your reward if you're on best behavior." The head groom addressed the guard again. "That's the other way we control them. The more they get them, the more they want them until they become addicted." The head groom paused for a moment. "And of course, they work as contraceptive devices too. We don't have to remove them when the girls get mounted."

Mackenzie froze in place as she heard the last words, they the faint vibration began to stimulate her again. "Oh, no, honey." The head groom spoke softly and condescendently. "No more cumming for you right now. But I have something else to keep you busy."