He modifies her, to suit their new shared breeding fetish.

Without thinking about it too much, Tom touches the coin in his pocket and makes a wish for Sarah to be fertile, perfectly suited for breeding, and always ready to breed.

After he makes the wish, he feels Sarah's body shiver beneath him as she lets out a low moan. With the two of them sufficiently isolated, and no longer visible from the trail, he quickly slides off her back and steps aside, eager to see what changes his wish has wrought.

The first thing Tom notices, gazing at her human upper body, is that Sarah's breasts are much larger, easily K cups. Good Lord, each of her tits is bigger than my head!, he thinks. Sarah doesn't realize anything has changed, giving her husband a smouldering look as she begins unbuttoning her blouse. "I love how my breasts have gotten bigger, since I changed. Don't you, Tom?" she says, as she finishes opening her blouse. She gives him another sexy look as she opens the snap on her front-clasp bra, letting her enormous breasts free.

Tom can only swallow and nod, due to his suddenly dry mouth. Her stares at her full, magnificent tits, with nipples thicker than his thumb and wide, dark brown areolae the size of his palm. Almost in a daze, he walks around Sarah's centaur body to take a look at her rear. Even from the front, and then the side, he can see that her mare hips have grown wider, and her horse-like ass has grown larger and fuller. Still, he isn't quite prepared for what he sees when she turns her body and flips up her horse tail to give him a better view. The cunt that lies between her huge, round butt cheeks is as different from the horse-pussy she had only a few minutes ago as that was to when she was human! Idly, he notes that her second set of mare-like breasts between her rear legs have also grown, if not as large as her human set, before turning his eyes back to her animalistic womanhood.

Tom stares at the huge, thick, meaty lips of his wife's pussy. As he watches, a thick line of lubricant slowly drools out of her snatch and down her equine thigh. Noticing his intent staring, Sarah flexes the muscles in her twat, and her dark pussy lips yawn open. Her gaping cunt reveals a pink, wet tunnel wide enough that he could fit his fist into her, and barely touch her walls. When her pussy wetly slaps closed again, another line of thick, clear lube trickles out, and he catches a whiff of sexual, womanly musk that announces that she is ready to fuck.

Nervously licking his lips, Tom reaches out to Sarah's huge ass, laying his hand on the thick meat of her rump right next to her horse-like pussy. Shocked and somewhat intimidated, he realizes that the opening to her cunt is several inches longer than his hand, and her labia are so thick and meaty that even using both of his hands, it would be a struggle to cover over the entirety of her cunt. What's more, even with her simply standing there relaxed, her pussy is partially gaping open, enough so that Tom feels a moment of doubt over whether she would even be able to feel his human cock in her centaur twat. Tom feels a lump in his throat, as he quietly worries that his last wish may have taken things just a bit too far.

Noticing that Tom is taking longer than usual to get to breeding her, Sarah glances over her shoulder to meet his eyes. Seeing him staring transfixed at her breeding-hole, she giggles to herself about her silly husband. Flaring her cunt, causing more of her juices to drip down from it, she seductively croons, "Fuck me." Swaying her plump rear from side to side, her voice dripping with desire just as much as her mare cunt, she says, "Fuck me, Tom!"

Shaken free from his moment of doubt, Tom needs no other invitation. The Coin hadn't steered him wrong yet, after all, and Sarah didn't seem at all concerned by the blatant size disparity of their genitalia. Almost frantically, he rips off his pants and climbs up onto a rock. Sarah simply backs up so that he can reach her beastly womanhood, her centaur tail waving back and forth, fanning more of her feminine musk towards him. As he grasps her hips, he finds that he can't fully escape his worries, thinking to himself, Will she even be able to feel me in her massive cunt? As he hesitates, Sarah looks at him over her shoulder, her hands working at her tits. "Go on, darling. Breed me!" she commands, before moaning as her ministrations produce a spray of milk from her thick nipples.

At that, Tom stops hesitating, and immediately rams himself into her, wildly fucking her huge pussy. He grins as his worries are washed away, loving this new, even wetter experience, as his balls clap against his wife's thick and meaty mare pussy. Seeing Sarah's twisting her human torso around, squeezing yet more milk out of her tits, a look of pure lust on her face, he wonders what part of his wish caused these changes, but can't find it in himself to really care. Changing the angle of his hips, Tom begins thrusting more deeply and forcefully into her massive cunt, while his hands wander across her huge ass and wide hips. Every time he thrusts into her, her cunt makes a loud wet squishing sound, and every time he pulls back, more and more of her juices splatter around his groin.

With a lusty groan, Tom brings his hand back and slaps Sarah on her horse ass, causing her mare twat to squeeze down, if only slightly, on his dick. The sight of her huge and now lactating breasts excites him even more, a huge grin stretching across his face. "I love you, Sarah," he grunts as he pounds her.

"I love you too! Ooh darling, your cock is so good!" Sarah says, continuing to maul her milky tits. In truth, she can barely feel her husband's human dick in her immense mare-like pussy, mostly just feeling his hips colliding with her rear and his balls slapping against her labia. Still, the feeling of repeated impacts against her huge centaur ass is pleasant in it's own way, because she knows that it's her mate that's mounting her. Her ardor continues to build, knowing that soon, he would grasp her hips, an adorable look of bliss on his face, and he would deposit his seed in her.

After only a short while, Tom feels his balls clench. Desperately, he tries to hold himself back, not wanting to cum so quickly, but it's too late. With an ashamed groan, he thrusts himself as deeply as he can into her horse cunt, and cums.

Seeing him stop moving, Sarah freezes as well, watching her husband finish in her with a lustful, almost hungry look. This is what she was waiting for. This is what she wanted, needed from her beloved mate. Continuing to pull at her thick nipples, Sarah bites her lower lip. She can feel his seed inside her, the muscles of her centauress pussy pulling his sperm deeper and deeper inside. She needs it in her womb. She needs it!

Once his orgasm finishes, Tom takes a step back on the rock, gazing down at Sarah's sopping wet horse cunt with mixed satisfaction and guilt. Damn, I feel like such a quick shot, he thinks to himself, embarrassing memories of his teenage years floating up. Despite his doubts, seeing thick strands of feminine lubricant drooling from her cunt, slimy strands still clinging to his cock and connecting them, he feels a deep sense of contentment. Hopping off the rock, he begins to step around her to go fetch the horse dildo tucked away in their pack, wanting to return the favor to her. As he does, he realizes that Sarah is still standing there, squeezing milk from her huge tits, her eyes glazed as she mutters to herself. Just as he's about to question her, Sarah twitches, and moans in orgasm, both of her breasts abruptly spraying a large amount of milk, and her pussy loudly squelching and squirting as well.

As she shudders in the wake of her own orgasm, Sarah says "God, I love that part." She then turns to Tom, leans down, and pulls him into a hug. Her huge, milky breasts make it quite possibly the most arousing hug that Tom has ever received from her, and as they passionately kiss, he can already feel himself stirring again. "I love you, Tom. That was a wonderful breeding!" she says.

Tom chuckles, taking a step back. Giving her a lusty look, he says, "Ready for round two?" his manhood already hardening again.

Before he can turn to fetch the dildo, Sarah simply smiles and shakes her head. "Mhmm, not yet. Perhaps after lunch I'll be ready again, darling."

Hearing this surprises Tom. Normally, after he's had his fun, he makes sure to pleasure Sarah. Then again, she did manage to have an orgasm, he thinks, shrugging it off.