"Yeah, no problem," you say, feeling a weight in the pit of your stomach. There goes your savings for the last few months...
"Great!" She says, smiling. "I think your wallet is in your pants back in the changing stall. I'll go run the charges real quick."
She heads back out through the metal door, closing it behind her. You look down at the massive diaper that you just bought, and run your hand down the backside of it, feeling the warm, bulging mass. The front is warm and bulging too, but more from the size of your erection than anything else. You look up at the field and see that several animals are looking up at you, staring blankly. You are just standing there in the dirt wearing nothing but your t-shirt and a huge horse diaper. Their stares make you uncomfortable, but a few minutes later the horse girl comes back through the metal door.
"Go ahead and bend over, holding on to that bar there." She points to the waist-high bar in front of you.
"Why?" you say in confusion and embarrassment, not wanting to raise your massive diaper so prominently in the air."
"It's the easiest way to get you cleaned up," she says. "My name is Jenny, by the way."
Distracted by the irony of her name, you bend over and grab the bar in front of of you.
Then suddenly without warning, you feel two strong yanks on your diaper, pulling it free and exposing your cock. You yelp in surprise, now standing half naked in the exposed open air. The smell of the diaper is overpowering, and you can hear flies buzzing about you. You look down at your cock and are surprised to see that it has nearly doubled in length, and has started gaining large black splotchy patches all over it. The front has become flat and wide, like a horses. "What the hell?!" you scream, but when you try to reach down to touch it, you realize that your hands have become tied to the bar in front of you by a thick rope.
"What?!?" You shout in confusion and surprise. "How did you do that? WHY did you do that?? What's happening to me?!"
"Ssshhhhhh", you hear Jenny say as she rubs her hand along your back. Her warm touch on your skin makes you shiver, and you let out a snort of pleasure. "I just don't want you to squirm for the next part."
You turn your head back, trying to find what happened to the diaper. Jenny must have removed it from around your legs while you were preoccupied with your hands. You see her holding a diaper, furry like the one you were wearing earlier, but completely clean of any manure. She folds it up and places it on a workbench by the wall. As you look at the diaper, you realize that this diaper is completely devoid of a horse tail.
"Wait, is that my diaper?" You ask. "She smiles and nods enthusiastically."
"But where's the tail?"
She smiles wider and walks back to you, and you feel a sharp tug at the base of your spine. You jump with a sudden and powerful realization: the horse tail didn't come off with the diaper, it is firmly attached to your butt.
"It's right here, silly!" She says
Your breathing quickens as you realize that you now have a horse cock and a horse tail. What else would happen to you? How do you get out of here? She removes the end of a pressure sprayer sprayer from the wall, and with the flick of a switch the massive machine comes to life. She begans spraying your butt and underside, and to your surprise the water isn't freezing cold. It's hot, like the water of a shower. She sprays off the manure coating your behind and cock, which hangs parallel to your bent-over torso. You still smell like a big horse, but the flies buzzing around you don't seem as bad when she puts the hose down.
She gets a large towel off a rack next to the table and begins to towel you off, but your shirt is still soaking wet.
"Jenny, what's happening to me?" You ask "Why do I have horse tail? What happened to my... package?"
She giggles as she continues to wipe the water from you "Isn't this what you wanted? You are turning into a colt, a baby horse, that is. Babies need diapers and milk, right?"