At Rarity's insistence, you find yourself entering the Carousel Boutique, Ponyville's only seamstress. "You simply must let me take your measurements," she had said, very quick to explain her rationale: it is better to get it down now, so she wouldn't have to rush later. The bell rings as you set foot inside, prompting a musical reply of "Coming~!" from the chambers behind the counter.

It is always a bit of a shock to see Rarity enter a room, as the unicorn is all dangerous curves, packed into a tasteful, frame-hugging dress that is a testament to her skills. A lesser artist's work would burst under the strain, or fold under the force of her jiggling assets, exposing Rarity's treasures to the world.

"Darling, I'm so glad you came in! If you would, stand on the dais and stay very still," she orders, sashaying over, the glow of her horn telekinetically fetching her measuring tape, and everything needed to record her findings.

Once you step up, Rarity is the picture of professionalism at first, unrolling the tape as her horn glows, pen scratching down to the millimeter your dimensions. As it goes on, however, Rarity's breathing grows heavier, body pressing into yours, and not merely the careless brushes of someone not paying attention to her body, but the needy weight of arousal. You can even swear she's muttering lurid things to herself, just under your ability to hear.

Eventually Rarity rises, keeping her back to you as her tools are stowed away, "I... just want one more measurement from you darling..."

With a glow of her horn, you suddenly feel your head start to swim, vision blurring at the edges as it grows difficult to concentrate. Your eyes see, but the brain doesn't interpret anything correctly. This only begins to fade after a journey through colors and light, from the perfumed boutique to its hidden underbelly, your body guided into a strange chair that lifts your ankles and holds them tight in fuzzy leather cuffs.

When this magical fog lifts, the vision before you is more of a shock than the simple presence of Rarity, her easy strut and luscious body, for she is now clad only in purple lingerie, from the tips of her fingers and toes in fingerless elbow gloves and thigh-high stirrup stockings, to the lacy bra that struggles valiantly to contain an overflowing bust.

Any excitement, however, turns to dread as you notice what juts from between her legs: almost two full feet of twitching black horse cock, steaming in the air and mingling Rarity's decadent perfume with the pungent animal musk of a futanari mare in rut.

"I really must apologize, but... it's your own fault. Coming to Ponyville with your delicious human body! I simply cannot control myself, darling!" Rarity smooths back her hair, looking over your nude form with blatant, shameless lust, "I really need measure two more things: how long you can take my love, and how DEEP that 'love' can fit inside you."