Sitri

The moment you step through the heavy metal door that leads to Sitri's lab, she grips your wrist with surprising strength, pulling you further inside with unfiltered excitement. The lab is a chaotic mix of advanced technological equipment, glowing vials in vibrant colors, and stacks of books on every available surface. Her small bat wings flick behind her as she practically drags you deeper into the organized chaos.

"Welcome to my lair!" Sitri declares with a grin, her red eyes gleaming with mischievous glee. She releases your wrist and gestures broadly. "As my new lab assistant, you’re going to enjoy all the perks: free room and board, a decent paycheck, occasional access to whatever experimental cocktails I’ve whipped up, and best of all..." She puffs her large chest and puts her hands on her hips, "hands-on experience in revolutionizing sexual biology!"

Before you can react, Sitri spins around dramatically, her lab coat flaring slightly and offering brief flashes of her barely-there succubus outfit beneath. She begins pacing back and forth as she speaks, her words coming faster and faster. "We’re working on groundbreaking discoveries here! Aphrodisiacs that adjust to an individual's unique pheromonal signature, stamina enhancers that make orcs blush, and of course… Oh, humans! Fascinating creatures… Did you know that human seminal generation rate is affected by environmental factors like stress? Or that the viscosity of human semen varies with diet? I have so many theories, SO many theories, that require testing!"

For a moment, she tapped her chin with the blunt edge of her pen as though deep in thought, before launching into one of her trademark jargon-filled rambles: "So! Essentially, I’ll need to study your fertility and gamete production under a variety of factors. Did you know that human seminal plasma carries up to 30 different proteins directly responsible for enzymatic reactions during capacitation? Oh! Not to mention the glycoproteins that mediate Cowper's fluid generation when dealing with non-synchronous interspecies pairings. This could have massive implications for-" Sitri catches herself midsentence and pushes her glasses up with her pen. "In simpler terms: I need to jerk you off and study your cum. Any objections?"

You lay on the exam table as Sitri fussed over her vials and tubes nearby. She approaches you with a large syringe filled with a glowing, faintly pink serum. Her red eyes lock onto yours briefly, giving you a reassuring, if somewhat predatory, smirk.

"This… this is going to be groundbreaking," Sitri murmurs, her excitement barely contained as she begins to clean the injection site with a cotton ball soaked in alcohol before lightly pressing the needle into your arm. You can feel the warmth spreading through your veins almost immediately, accompanied by an unfamiliar tingling sensation. "This serum took months...no, years to synthesize correctly. It’s designed to interact specifically with human spongy tissues, enhancing blood flow with minimal refractory period interruptions."

She discards the used cotton ball and reaches for a small bandage dispenser. Sitri carefully places a cute, pink, succubus-themed bandage over the injection site.

Her excitement bubbles over as she continues her explanation. "Essentially, this serum will increase both the duration and intensity of your erections by hyper-stimulating your cavernous bodies while minimizing synaptic fatigue,effectively shortening your refractory periods. The implications this has for understanding physiological compatibility could be..."

Catching herself rambling, Sitri shakes her head with a wry smile. "Ah, sorry! Got a bit carried away there." Her expression turned serious, as she shoots you a hungry look. "We’re gonna put that serum to the test right now."

Sitri pulls out a sleek, digital stopwatch from her lab coat pocket. "Starting… now." Before you can fully process her words, Sitri climbs onto the exam table, straddling your hips with confident ease.

"I’m going to ride you," she stated bluntly, her voice holding no room for protest, "Nonstop. Until you can’t get hard anymore." Her eager grin widened as her hands settled on your chest for support, her wings fluttering excitedly behind her. "For science… of course."

And with that, Sitri slams her hips down against yours, starting her latest wild experiment.

Sitri leans back in her swivel chair, spinning it slightly as she gazes at you with a smug grin plastered across her face.

"You know," she begins, absentmindedly twirling a lock of her purple hair between her fingers while balancing a clipboard on her knee, "after all these countless experiments we've done together, I think I've really tapped into the science of succubus-human compatibility."

Sitri reaches into a nearby drawer and retrieves a neatly folded piece of paper. She smooths it out on the table, revealing handwritten names and fantasy races, each entry accompanied by heart emojis and enthusiastic comments. Her smile widens as she taps the paper with an authoritative finger.

"So here's the deal, I've got more data on you and me than I know what to do with." She says with a playful wink, her wings fluttering slightly in amusement. "What kind of scientist would I be if I didn't expand my sample size?"

She hands you the paper with dramatic flair. The list is quite diverse, including entries like 'Fenra – Orc Dominatrix,' 'Velithia – Shy Elf Mage,' and 'Ky'ari – Hyper Horny Foxgirl.' And at the bottom, there's a cute note that reads: 'P.S.: There are TONS more where these came from if none of these fit your fancy!'

"Oh, don't act so surprised." She chuckles as she gets up from the chair. "Turns out there's this forum where girls with fetishes for human men post; a perfect pool of potential test subjects, naturally." Her words drip with sarcasm, though there's an underlying tone that suggests she's entirely serious. "And oh my, they all eagerly agreed to step into the lab for hands-on observation once I mentioned that YOU were participating!"

Sitri approaches you from behind, her hand rests on your shoulder, squeezing lightly as she leans in closer. "So," she says into your ear, "which girl do you want to fuck while I watch and take notes? Pick a name off that little list." Despite the tease in her voice, there's an edge of professionalism that suggests she's ready to handle this experiment seriously, regardless of its nature. "I'll watch everything with strictly professional interest, of course." She gives another sly smile. "Maybe give you some words of encouragement if you need them."