Withania fidgeted around Twilight whilst the princess scratched out more notes at her lab desk, along with what looked like a note to Spike.

“I can’t eat you! You’re a princess!” wailed Withania, placing her hoof on Twilight’s chest in protest.

“Yes and as a princess I want to do this. Think of the science, Withania! Think how much we’ll learn on a trip through your insides!”

“But how will we learn anything? When I get eaten I usually pass out as soon as I start going soft… Plus we don’t know if the reformation spell works for me now…”

“BACKUP will work for any living predator that consumes their prey,” Twilight reminded her, “Your muscle memory knows what you ate and what you digested, it’s that memory that the spell calls on to rebuild your prey. With me casting it we can go a full forty-eight hours into the process. I’m going to combine it with a mind-linking spell I developed myself - it feeds my experiences directly into your memories, so whatever happens to me will be recorded in your brain for later retrieval. All you have to do is sit back and enjoy me!”

Were it not for the fact that Withania herself was quite happy to feed herself to somepony else, she would’ve thought that the princess had gone quite mad. But all things as they were she could see a combination of scientific research and being prey to an exotic new predator was too much for Twilight to resist.

Meanwhile, Twilight had opened a storage cupboard along one of the walls and dragged out a huge plush bean-bag that looked like a giant ravioli, big enough for two ponies to comfortably share. She sat down on one end of it and patted the other invitingly. Withania reluctantly sidled onto the soft cushion, trying not to stare at the princess sitting almost eagerly in front of her.

“Now then, once you’ve eaten me, don’t do anything, just let your body do whatever it wants to. Unless you feel like there’s something you’re supposed to do - in which case do that. Does that make sense?”

“Umm…”

“Perfect!” went on Twilight, magicking the letter she’d written out of the air, “Spike has a letter from me explaining that my schedule is full for the next two days, so you don’t have to worry about me! Let’s get started!”

She leaned forward eagerly and dived straight into a kiss on Withania’s lips. Her horn glowed and Withania felt a cool touch on the crest of her forehead, where a unicorn’s horn would be. She looked up and saw a curved beam of magic linking her to Twilight’s horn, and she felt a rush of emotion she didn’t recognise as her own - excitement of discovery, curiosity of the unknown, expectation of pleasure.

“Now we can feel each other’s senses, you’ll feel what it’s like to be me in this situation as well as your own experience,” explained Twilight between gentle pecks at Withania’s muzzle, “I’ll lead, just do what feels right…”

The princess parted Withania’s lips and brushed their tongues, before gently prying the earth mare’s mouth open with her muzzle, licking and smelling the sweet nectar inside. Withania sat with her back straight, letting the alicorn lean into her, but hesitant.

What am I going to say when someone asks me where Twilight went?! she thought, looking around the room, rather than at Princess Twilight Sparkle slowly trying to insert her muzzle into her own, I know she’s the element of magic, but she doesn’t know what my body might do!

Twilight seemed to pick up on her lack of enthusiasm and pulled back, her nose stained yellow with Withania’s saliva. She had a lustful look in her eyes, but thanks to the linking spell Withania could feel that Twilight was still fully in control of herself.

“H’mm… If I recall you tend to stimulate the Tegmen flower at the beginning - that must be where I’m going wrong here…” she said, and reached one hoof down between Withania’s hind legs, seeking out her sensitive area. Withania’s gasp betrayed her attempts to stay composed.

“Wh-what? I didn’t mention that in my notes!” she protested, her voice shaking as the princess of friendship parted her nether lips with the tip of her hoof and traced the slick fluid within up her slit.

“That bit was in the stories you also have on your desk,” explained Twilight in sultry tones, “I can read at six hundred words per minute with a one hundred percent comprehension. I’ve read all your little adventures while you were asleep this morning…”

While Twilight’s idea of pillow-talk didn’t really do anything for Withania, the idea that she’d read the errotic stories left on the desk did bring a dark green flush to her cheeks, and she felt Twilight’s massaging hoof down in her nethers spread her wide in response. As the heat of stimulation flooded through her body, Withania felt the pang of lust again, and with the flip of a switch, the alicorn in front of her suddenly looked drastically more appealing.

“Turn around,” Withania whispered, leaning in to kiss Twilight again, “I won’t get past your horn like this…”

“Don’t worry I have just the thing,” replied Twilight, and with a quick glance to the shelves along the wall, a bottle floated over in her magical aura, from which she plucked out a spherical blue pill. She pulled away from Withania and quickly swallowed it, before diving back into the kiss.

Withania had no idea what was going on here, but she nearly spluttered in shock as blue spots appeared on Twilight’s long, elegant alicorn horn, and it began to bend like a wilting flower, until it was flexible enough for Twilight to brush back with her fringe - supple and no longer threatening to stab Withania in the throat.

The clear obstruction now somehow out of the way, Withania pushed into another long kiss, instinctively exhaling through her nose as Twilight breathed in the intoxicating scent. She could feel the princess’ desires, her will to let Withania take over and suspend her deep within, the lust growing until Withania’s thoughts became Twilight’s experience.

Feeling the quivering desires from Withania’s seeping pussy, Twilight once again parted her lips, pushing her nose into the earth pony’s mouth. Withania responded by opening her jaws as wide as she could, letting them stretch wide over the rest of Twilight’s muzzle, giving her a glimpse of the pale green interior glistening with the aromatic nectar that had been sending other ponies into a drunken frenzy. It was delicious, but thankfully Twilight was able to keep her head as those dripping jaws stretched up to her ears, pressing her floppy horn back.

As her glowing horn brushed along the roof of Withania’s mouth, Twilight heard, or almost felt, a deep moan of pleasure as her partner tasted raw magic for the first time, a cool, tingling sensation not unlike peppermint, a taste that enhanced flavours around it and stimulated the mouth. She felt Withania wrap her forelegs around her and draw her into a close embrace, which also served to pressed Twilight’s slick hoof into the tight, but stretchy folds down below.

Twisting her head slightly to make sure she was getting evenly coated in golden saliva, Twilight pushed with her hind legs, and her brow touched the back of Withania’s throat, triggering it to clench and grasp her head. Withania instinctively pushed down, her mouth sinking over the princess’ twitching body to the shoulder blades. It was not her first time entering another pony’s body this way - but sweet floral smell and alluring atmosphere inside Withania was unlike anything she’d felt. The hybrid pony’s esophagus stretched easily to accommodate her wings, but compressed about them with ease, creating a rippling wave that caused her to lurch forward.

As Twilight’s muzzle poked through into Withania’s stomach, she was met with a flood of nectar. With not even a bubble of air, she began to drink, gulping mouthful after mouthful as if she had been lost in the desert. Withania’s body vibrated with another moan of pleasure, feeling the undulations of Twilight’s swallowing traveling back up her throat. She leaned forward into the space where the princess had been sitting, her body now occupying the entire beanbag, her belly expanded to accommodate alicorn. Twilight felt Withania’s jaws slide down her rump, legs, and finally close over her hooves, with nothing more than a purple and pink tail sticking out behind.

Twilight found herself forced into a foetal position by the plush walls of Withania’s stomach. She held her breath and gingerly tried to open her eyes. To her amazement, the nectar didn’t sting, and in the dim light of her horn, she could see the pale, almost white, lining of her new home - although everything was tinted yellow by the nectar she was suspended in.

She wanted to cast a spell for underwater breathing, however she felt the tightness in her lungs already - she’d left it too late! She put a hoof out against the stomach wall, pressing out to try and signal to Withania, and felt a corresponding press back, Withania rubbed her own hoof against her soft belly in response, feeling her catch move inside her.

Withania! Withania I can’t breath! Twilight shouted in her mind, hoping that her host would hear over their mental link.

“Sssshhh,” cooed Withania, laying on her belly while drawing circles in her side with one hoof, “Stay calm, this will be unpleasant for a moment, but then comes the bliss…”

Twilight pressed her hoof into Withania’s through the soft padding of her belly, as if they were holding hooves, and choked bubbles out from her mouth. Her lungs drew in the soupy fluid around her, and then after a few false coughs and gasps - she was breathing again. She could feel the fluid rush in and out of her larynx, she watched in awe as the last few bubbles of air floated to the top of the stomach, and then her surroundings convulsed as Withania belched, releasing the trapped air and sealing Twilight in.

It’s amazing… Twilight thought, I can feel it swirling inside of me, it’s like Withania herself is taking over my body…

Outside, Withania hiccuped a few times as the last of the air from inside her meal escaped, and she turned over onto her back, feeling the glorious weight of her belly wobble on top of her. She’d actually eaten an alicorn princess. Twilight was hers now, she could feel her body sapping magic, nutrients, and a dozen different species of microscopic pollen particles off of her body. Her drenched pussy winked to remind her that Twilight hadn’t finished her off before she’d swallowed her, but she couldn’t reach to do anything.

She rolled over again, and leaned forward so her neck touched the beanbag and her tail stuck up into the air, and gently began to press her hips back and forth against the soft and plush gut between them, until she found the perfect angle. The rush of lustful energy flowed back along Twilight’s mental link until the princess inside her could no longer keep her own hooves away from her nethers, parting her folds and pressing her button repeatedly, her juices leaking into the amber mass she was suspended in.

Withania pressed harder, squashing the plush mass of her belly in pulses, willing her nectar to drive deep inside the captive princess, to flood her pussy, her anus, everything until there was no part of the alicorn she wasn’t touching - she bit down in the bean bag as she felt her aching flower contract, a single bead of vicious yellow nectar squeezing out to run down the inside of her thigh while the two ponies simultaneously relaxed into a post-coitus stupor.

Inside, Twilight breathed the fluid of her surroundings in smooth gasps. The sensation of her surroundings feeding off of her was exhilarating, not a life-sapping tiredness, but the intimate embrace of sharing body heat, and she had more than enough magic to spare for her host to enjoy. The fleshy green walls had closed in around her, pressing her limbs together into unnatural positions, although with no pain. Her joints and flesh had softened in the golden brew, she was malleable, content to sit as she was until Withania’s surrounding drowsiness began to take hold, and in the soft candle flicker of her horn’s glow, she drifted out of consciousness.

Author's Note

I'm not one to look a gift horse in the mouth. Apparently neither is Twilight - at least figuratively speaking anyway... https://derpibooru.org/1771471