"...a pony."
"You want to be a horse?" You ask puzzled.
"Well..." she blushes. "I love horses. I just want to see what it's like."
The changes begin immediately. Her long chestnut hair begins to change form as a mane forms, along with a long brown ponytail pushes out the top of her jeans. You hurriedly help her remove her clothing as the changes progress, chestnut fur spreading across her athletic frame. Her hands soon become useless though as they are manipulated into hard black hooves.
"Oh my god, this is so wierd!" She says, although you can't tell whether she is loving this or regretting it.
Not long later, she has all the features of a horse, although she mostly retains her human frame. "Wow...this is amazing!" She says, looking down at herself naked.
"I've got to admit...it's kind of sexy," you respond, taken aback.
"Well," she puts a hoof on your shoulder and leans in seductively. "Want to take advantage of it?"