Twilight looked over the spewing paper that came pouring out of a machine. "Hmm... There certainly is something out of the norm, but I can't quite isolate what it is, beyond the obvious physical differences. What I'd like to do is collect a sample." She trotted off and returned with a large glass container. Her magic wrapped around its lip and pulled it carefully until it had a wide lip. "It would be impractical to go with saliva, that leaves urine or semen. Either should be fine." She waved the bottle at me as if I should pick.
Funny story, perhaps due to Cindy's eager optimizations, I just didn't go to the bathroom all that often. Whatever went in, stayed in, and I didn't feel the urge to eat or drink unless I actually put it to work. I didn't feel ready to produce any samples for her the ''easy' way. I said as much. "I don't have to go to the bathroom right now."
Twilight nodded. "Well..." She looked like she was ready to go ahead and do something, but stopped herself. That bottle had moved towards me before jerking back. "Will, may I extract a sample? I'll be careful, promise. Your comfort is important to me and I understand you are a pony, not just a test subject."
Some of that felt stilted and artificial, but that she'd bothered to say it and waited for my permission did a lot to calm me down. I smiled at her and nodded. "Go ahead, Twilight, but the parts you'd want are currently pressed against this bench."
Twilight blushed at that. "O-oh! Right. Actually..." She turned towards the stairs leading upwards. "Fast Change! Could you come here?!"
Her shout summoned a unicorn scrambling down the stairs. Oddly, the new unicorn looked just like Twilight. "What's up, Twi?"
Twilight blinked at her clone. "Fast... Er, I needed your specific expertise."
Fast looked at me, strapped to a bench, then back at Twi. She arced a brow quietly.
Twilight waved her vial at me. "I need a sample from this pony. They aren't prepared to product urine, so semen is our option. As far as I'm aware, they are a fully functional hermaphrodite, so if you could gently stimulate them to ejaculation, that would be best." She sent the vial to Fast, who took it in her own magic and wandered towards me with a curious expression.
"Are you alright with this?"
The fact that she asked was a good mark for their basic, uh, well, humanity felt like an odd word for ponies. They were the real deal. They weren't changed humans. Decency! That was a fine word for it. "It's to help understand things. If it can help put things right, then I'm quite fine with it."
Fast flashed a bright smile before she wrapped her magic around those straps and gently undid them. "Then let's get you comfortable. Go ahead and lie down for me, and tell me what you like in a mare."
I stepped off the bench and looked between the two clones. She seemed to pick up on my inspection and giggled. "I can be almost anything I want, though I admit I never tried anything like you before, so let's not do that."
Twilight rolled a hoof in the air. "You're not dating them, Fast."
Fast blushed softly. "Twilight, this was your idea. Don't ruin the mood. They aren't some mindless beast to be milked and tossed aside." Her horn glowed softly, but I didn't see what she was manipulating until a soft stroke traveled up along my sheath, then down over my balls, gently exploring and teasing with little micro-scratches that made me start to firm swiftly. "There we are, now tell me about yourself."
I stretched out slowly, giving an almost-purr at the treatment. Her magic was quite skilled at seeking out where to stroke. She wasn't a mate of mine, but I supposed filling a vial for study didn't really count as an intimate encounter. "You're doing just fine, Fast Change. You can keep looking like Twilight or anyone else." I closed my eyes and settled, surrendering to the slowly hasting pulls at my large horse cock. "Just... fine." I meant it, each pull along that excited pole was a pleasure, and the way she tickled and teased at the same time... She was more skilled with her magic than any of us were, just in terms of raw ability to handle things, multiple things, all at once.
Fast giggled. "Aw, he's like a big happy doggy." Her voice held no malice, even if she was comparing me to a dog. I couldn't muster up much ire about it as she began to stroke faster and faster. Her magic grip split again, one part working up and down my shaft, pulling at the sensitive flesh just hard enough while another began to swirl around and around my flattened head. "Go on and fill 'er up. Say, anyone ever tell you you look a little like Princess Cadance?"
Twilight made a curious noise. "I suppose she does at that... Maybe that's why I feel comfortable, but also what sets me on edge. You're so close, but clearly not right."
Fast snorted softly. "Right into the surreal." Her grip on my balls became less scratching and spread out, gently stroking and holding those furry seed factories. "Now come on, and cum. There's no reason to hold back, hmm, unless you're just enjoying it that much? Is that it? Are you holding it in so that I'll keep teasing you. I can imagine that thought, struggling to hold back the tide of hot, virile, ready seed just so I'll keep playing with you a little longer. You dirty little pony..."
"T-that isn't necessary," came Twilight's voice. She was clearly flustered at the raunchy talking.
Required or not, it did the trick of working me up. I grunted as I thrust into the air. I wanted to climax, but, much as she said, it did feel really nice, and I was enjoying it. I didn't want to get too intimate with this pony that wasn't part of my herd and tried to relax into climax, but relaxing was counterproductive. I felt a presence behind me and my nethers were split with a new reach of magic. "May I taste her?"
"N-no! That's entirely unnecessary for this. Fast, please, focus."
"But I am focused." That magical intruder pushed into me, thick and ribbed and thrusting like an eager beast. I wasn't normally taken both ways at once like that! I snapped my eyes open even as a moan forced its way out of me. I could see a Twilight in front of me, looking red as a beet and glancing away from me. Behind me, another Twilight leered with a brightly glowing horn as she worked me over. "Somepony's really enjoying themselves, hmm. Go on, fill 'er up for momma." She sauntered up to me and leaned in, not interrupted by her own magical dildo that was pistoning into me with wild abandon.
I felt the shadow of a doubt in me, but thinking was hard with the pleasure coursing through me. I barely managed a hiss before her tongue touched along my pouted nethers. She lapped at me eagerly while thrusting deep. "Mmm, you taste interesting, my otherworldly stallion. Stop holding back. You can't resist me forever."
Something clicked. I thrust forward against the lover that wasn't there. I felt the vial slip over my swollen cock and I fired into it. The fluid rushed in so powerfully that much of it came right back out and splattered to the ground, but I had more where the first one came. I shuddered in place as my peak washed over me in powerful waves of ecstasy. The poor vial was overflowing, and I was making quite a bit of a mess on the ground, but I still felt her. She was nuzzling into me. The fur of her snout tickled in the right way, making me tremble and keeping the release going just a little longer.
As it came to a halt, I slid to the ground bonelessly. That vial was pulled up and away, drenched in seed and filled to the top with my offering. "See, that wasn't so bad. Here you are, Twi."
I huffed and puffed for air and rolled to the side. "I don't suppose there's a shower down here?"
Fast leaned forward from behind me. "Aw, did I leave you all wet and messy?" She had no shame, at least as far as I could tell.
Twilight shook her head quickly. "Stop teasing him, er, her, them. Thank you, Fast, that will be all."
~I didn't think you would do that with them,~ came Cindy's voice in my head. ~They're not part of the herd, and you may infect them.~ There was a pause. ~Was it nice?~
~The one called Fast Change is almost worryingly good at it. She did the work. It was to fill a vial with cum, for study.~
~You can fool yourself all you want. You enjoyed that, a lot.~ Cindy didn't sound angry. ~I want to try, later, if she wants to. Was she touching you? You really should be more careful.~
I shook my head, to Twilight and Fast's confusion. ~No, she was using her magic.~ I remembered then the licking and nuzzling feelings, and that click. I quickly flipped my vision over to feel sources of the 'gift' around me. Fast was rapidly becoming brighter as the infection fully seeped into her body.
Fast smiled at me. "That was nice. I hope it was for you too." She ruffled her purple wings softly. "Mmm, I feel really good right now. Can we keep them, Twi?"
Twilight stomped a hoof. "Absolutely not! Thank you, Fast, Will. I should examine this." She moved to retreat with the specimen in hand. "I'll be up when I'm done."
Fast came up beside me and bumped flank-to-flank. "Let's go. She's about to go into full nerd mode, and there's no fun to be had when she's like that, even if she is adorable while she's zoned out like that."
I followed Fast towards the stairs even as I worried about her. Was she experiencing the urges and drives that had driven so many humans to the breaking point? How would we cleanse her? There was no equine energy misbalance in her, only the presence of the void. Maybe we could just burn it out, like any human, but what if she reacted differently? She wasn't a human. She was a pony, born and raised.
She looked over her shoulder at me. "Are you staring at me?" She asked it in an accusing tone before her eyes went half-lidded. She gave me that sultry stare without saying anything, but promising so much more, if I would but accept the offer. I became more convinced that she was being overwhelmed by the gift.
~Cindy, we have a problem. Fast is infected, and I'm almost certain she's being mentally overtaken by it.~
~Bring her to the living room, we're all here. We'll help.~