I used NovelAI's unlimited gen membership for $25 a month. Note that "unlimited" is kind of a lie, it's only unlimited if you're under a certain resolution and only if you're not using any of the advanced features. Upscaling and other features cost the on-site currency, which the membership gets you 10000 a month. That should be more than enough for a month, but you can burn through it quickly since NAI gens so quickly.

The dim purple glow of the candlelight in Rarity’s plush bedroom painted everything in a sultry violet haze. The air was thick with the sweet perfume of lavender oil she had dabbed on her horns and the deeper, musky tang of arousal already thickening the air. A low, rhythmic panting filled the room—Spike’s. The small green dragon’s chest heaved against the silk sheets as he lay sprawled on his back, one stubby arm reaching up, the other braced against Rarity’s massive purple thigh.

She looked every inch the dream. The elegant unicorn pony who once designed the most exquisite gowns now posed on all fours like a goddess of pure carnality. Her long, glossy purple mane cascaded over one shoulder in perfect waves, the tip brushing the floor. Her white coat gleamed with a faint sheen of sweat, the diamond-shaped cutie marks on her flanks shining like polished sapphires. Those striking sapphire eyes were half-lidded, lashes fluttering with seductive weight, while her lips curved into a knowing, teasing smile. A faint blush painted her cheeks a rosy pink, the kind that only ever appeared when she was truly, deeply turned on. Rarity’s massive, jiggly ass was raised high, cheeks spread wide by her own hoofed hands as she presented herself. Her tail—thick, luxurious, and the exact shade of her mane—curled lazily to the side, the tuft brushing against her dripping slit.

“Ohhh, Spike, darling,” she purred, voice a velvet melody that made the tiny dragon’s cock twitch. “I must admit… I didn’t expect you to be this… enthusiastic. Or quite this *endowed*.”

Spike’s face was flushed green, ears flattened in shy bliss. His voice came out in that signature squeaky, enthusiastic wheeze—nothing like the gentle, bookish dragon who spent his days reading poetry or napping on Rarity’s bed. Instead, his huge body trembled with barely contained hunger. “R-Rarity… I-I tried to be gentle… but—ahh!—it feels *so* good when you look at me like that…”

His cock—Gods, his cock—was already straining against the soft white fur of his belly. It wasn’t just big. It was *monstrous*. Easily as long as Rarity’s forearm, thick as her wrist, the shaft a deep, angry pink that curved upward with veins pulsing like living rivers. The tip flared into a broad, glistening head already leaking thick strands of precum that dripped in heavy ropes onto the sheets. And the *balls*—*titanic, churning orbs*—hung low between his thighs, each one the size of a grapefruit, heavy and swollen. They shifted with every shallow breath, churning and gurgling like they were filled with gallons upon gallons of the thickest, most virile seed she had ever tasted.

Rarity’s horn glowed with a soft pink light as she leaned down. Her tongue—long, pink, and surprisingly dexterous—lapped slowly from the base of his shaft all the way up, swirling around the bulbous head. Spike squeaked, hips bucking involuntarily. “Mmmph—Rarity! That’s—oh stars, your tongue feels *amazing* on my cock…”

She hummed, the vibration traveling straight through his length. “Mmm, I can see why you’re so eager, Spike. Look at you… already drooling for your big bad Rarity. But darling… this?” She wrapped her elegant fingers around the impossibly thick girth, giving one slow, gentle stroke. The skin was velvet-soft, the veins throbbing. “This is *monstrous*. It’s putting every stallion I’ve ever seduced to shame. I can barely wrap my hoof around you, my sweet little dragon.”

Spike’s eyes rolled back, a broken moan escaping him. “I-I know… I-I can’t help it… the second you get wet I just… I just *need* to be inside you…” His voice cracked, shy and overwhelmed, the same Spike who used to blush at her compliments now reduced to a whimpering mess. “You’re so *sexy*, Rarity… so *perfect*. I don’t deserve a pony like you… but I’m so glad it’s me.”

She giggled, the sound bright and melodic, yet laced with genuine hunger. “Oh, but you *do* deserve me, Spike. Every inch of this ridiculous monster cock, these massive churning balls, and that insatiable little heart you think you hide.” She leaned in again, taking the fat head into her mouth with a wet *suck*, cheeks hollowing as she worked it with expert skill. Spike’s front legs scrabbled at the sheets. “Mmmph—Spike! You taste like strawberries and pure want… mmm, I could suck this forever…”

The wet sounds filled the room—*slurp, glurk, suck*—every filthy noise amplified by the confined space. Spikes’ precum was already coating her tongue in salty-sweet ribbons. Her own pussy was visibly dripping, clear arousal sliding down her thighs and pooling beneath her.

But Rarity wasn’t done teasing. She pulled off with a wet pop, strings of saliva connecting her lips to his throbbing cock. She turned just enough to show off the tight, puffy slit of her sex, winking clitoris glistening in the candlelight. “Mmm… but I think it’s time I *felt* what’s been making me so wet. Come here, my big green boy.”

Spike scrambled forward on shaky legs, cock slapping heavily against his own belly with a meaty *thwack*. Rarity reached back, spreading herself wider with both hands. The red head of his cock—still glistening from her mouth—nudged teasingly against her slick folds. “Ah—ahh! Rarity—slow—slow down—”

“Shhh, darling,” she cooed, voice dripping with smug affection. “You’re the one with the *titanic* balls. Let me feel them stretch me open.”

She sank down.

The first inch popped inside with a wet *schlick*, Rarity’s walls fluttering around the impossible girth. Spike threw his head back, a high, broken “Rarity—!” tearing from his throat. Her pussy was *tight*—velvety, rippling, milking him like a fist. The head alone had her gasping, back arching, massive breasts swinging and slapping together.

More inches followed. Inch by inch. Her walls stretched obscenely, lips gripping him like they never wanted to let go. She bottomed out with a shuddering moan, the swollen head kissing her cervix. “*Oh*—Spike—*fuck*—you’re so *deep*—it’s filling me up—mmmph—your balls are *pressing* against me—Gods, I can feel how full they are…”

Spike’s voice was pure bliss and panic. “I-I’m sorry—Rarity—I tried to hold back—ahh!—but your pussy feels *too* good—your walls are squeezing me so tight—I can’t stop cumming inside you—please—please let me—”

She began to move.

It was slow at first—deep, rolling rolls of her hips that made her massive ass jiggle and clap softly against his thighs. Then faster. Then *wild*. The wet *schlick-schlick-schlick* of her pussy swallowing his monstrous cock filled the room like a filthy symphony. Every thrust made her breasts bounce, nipples stiff and dark. Her horn glowed brighter, sending waves of pleasure straight down her spine.

Spike’s hands—small and clumsy—gripped her hips, claws digging in just enough to leave faint pink marks. His face was a mask of pure, overwhelmed joy and shy adoration. “Rarity—Rarity—Rarity—!” he chanted between moans, voice cracking higher with every thrust. “You’re so *beautiful*—look at you—taking my cock like it was made for you—*fuck*—I’m gonna—ahh!—I’m gonna cum so much—my balls are *churning*—gallons—gallons of it—there’s so much I can’t even—*ahh!*—I love you—*love* you so much—”

She leaned forward, mane spilling over his face like a purple curtain, whispering hotly into his ear while she rode him harder. “Cum for me, Spike… fill your Rarity’s womb… I want every last drop… I want you to pump me *so* full…”

The dam broke.

Spike’s entire body seized. His massive balls drew up tight, then began to *pulse*. Thick, heavy jets erupted deep inside her—*boop… boop… boop*—each one hotter and thicker than the last. The sheer volume made her eyes roll back; she felt her belly *swell* slightly, the pressure pressing against her cervix. She came hard, walls clamping down, milking every single rope of cum from his titanic balls until they were empty and sagging.

Rarity collapsed forward onto Spike’s chest, both of them panting. Her pussy fluttered around his still-throbbing cock, squeezing out the last few drops. She kissed his snout gently, then nipped his lower lip.

“Mmm… well, Spike,” she murmured, voice hoarse with satisfaction. “I *did* expect a big cock… but this? This is going to ruin me for every other lover I’ve ever had.”

Spike’s ears were flat, eyes glassy and happy, a shy little grin on his face even as his cock gave one final, lazy twitch. “I… I’ll do my best to be *even bigger* next time, Rarity…”

She laughed—bright, melodic, and utterly content—rolling off him to cuddle his smaller body against her massive, cum-filled curves.

“Darling,” she purred, stroking his mane, “you already are. And I wouldn’t have it any other way.”

The candles burned lower. The room smelled of sex and lavender and pure, unrestrained love. And somewhere deep inside her, Spike’s monster cock—and the gallons of ultra-virile cum he could produce—had already begun to stir again.

Rarity smiled into the purple darkness, whispering the same words she always did when she knew she was utterly, helplessly in love:

“My little Spikey-Wikey… I can’t wait to see what else you can do tonight.”