Ginny wants more from her steed

Ginny’s cock eases gradually into Tonks’ pussy, drawing gasps and shudders from both with each inch. Too soon, though, Ginny’s head bumps up against something she can’t push through, “Hnng, Tonks, there’s something blocking -ung- me…”

With a strained voice, Tonks replies, “Th-th-that’s my c-cervi-hnngkuh!”

“We’ll move it, bitch, I’m going deeper!” Ginny doesn’t wait for a reply, she just shoves herself further in. Tonks yelps and quickly starts stretching her vagina centimeter by centimeter, barely keeping ahead of Ginny’s spelunking rod. Enjoying her extended playground, Ginny declares, “Now that’s more like it! This is a much smoother ride, you’re becoming a lovely mare, Tonks. You know what, you’ve got the sheathe for it, so go ahead and make yourself look the part!”

Tonks looks back over her shoulder at her rider. Knowing her place, she bites her tongue and starts making changes. Aiming to please, she starts by plumping up her butt. Ginny admires the sudden increase in size and thrusts faster, much to Tonks’ dismay. With the heft of her ass weighing on her weakening legs, Tonks decides to go back to front. Her thighs expand to match her hips, and her toes blend together into one hoof at the end of each leg. The proportions of her legs shift, and a hairy tail poofs out of her tailbone, tickling Ginny’s face and tits unexpectedly.

Spitting out her tail hair, Ginny calls out, “Kinky! But don’t think you’re done yet!” Tonks opens her mouth to speak, but Ginny cuts her off, “Horses don’t talk, so you better handle that too. You can always respond ‘Neigh’ for no, though!”

Tonks nods obediently, and continues augmenting herself. She concentrates to elongate her nose into a horse’s snout, and her hair rearranges into a pink Mohawk. Her ears extend and flick reactively, and move up the sides of her head. Fur sprouts from her skin, starting from the base of her new tail, and Ginny moans with pleasure as she kneads her fingers into the velvety coat. It spreads across Tonks’ whole body, including her still human parts, but with it comes swift changes. Tonks’ arms get a similar treatment to her legs, pushing her previously sloped stance up and makes her back relatively flat again. Her torso expands, bulging to be much thicker and heavier, and her neck elongates and thickens with it.

Before long, Tonks has completely reworked her body into that of a horse. Ginny grins from ear to ear and keeps up her pace as she fucks her new mount, “Best pony ride ever!” Tonks whinnies, though what she means by it is lost to her new voice.