> The next morning, you hear a knocking at the door.
> It's Spike, to your surprise.
"Good morning, Spike, how can I help you?"
> He yawns.
> "Mornin'. You got a letter from Celestia. Mind if I crash on your couch?"
> You take the scroll with a certain amount of apprehension.
"Yeah, go for it dude."
> He staggers off, and you lean against the outside of your house, reading by the morning light.
 
~
To Anonymous, my little human.
 
Meet me outside the library when you get this.
 
From,
Princess Celestia of Equestria
~
 
> worry.png
> You run inside, grabbing your deoderant and applying in the way to the bathroom.
> A quick comb through your hair, and you are ready as you will ever be.
> You set off at a jog, not wanting to build up to much sweat.
> The morning is cool, and you make good time.
> Celestia waits by the door, and smiles when she sees you.
> You walk to her and perform a short bow.
"Good morning, Princess. How can I help you?"
> She glances at the sun.
> "It is rather nice, isn't it? Anonymous, I have asked you here in regards to some letters I have received over the past two days."
> Uh oh.
> She levitates two scrolls in front of you.
> "Once you read them, I think your purpose here will become clear."
> With no little apprehension you pick up the first one.
 
~
Dear Princess Celestia,
 
Today I learned that sometimes, it takes kindness and generosity to help a friend open up about themselves. Even if you do start off on the wrong hoof, if you apologize with sincerity, your feelings will get through, and you will get to see the hot monkey dick.
 
Your faithful student,
Twilight Sparkle.
~
 
> You look up at Celestia in confusion.
"Does this really qualify as a friendship report?"
> She nods pleasantly.
> "Are you not friends with Fluttershy and Rarity?"
"Fair enough. Let's see the next one."
> You swap scrolls, and brace yourself.
 
~
Dear Princess Celestia,
 
Today I learned that my friends are sneaky, clever, and hormonal mares. I'm not entirely sure what went on, but now my other three best friends smell strongly of Anonymous. I learned that sometimes, research isn't enough. You have to go out and seduce the human.
 
Your faithful student,
Twilight Sparkle.
~
 
> You hand the scroll back with shaking hands.
"She's gone a little crazy, hasn't she?"
> Celestia nods.
> "Just a bit. Xenobiology has been one of her favored subjects in the past, one of thousands, but now it is a large focus of her studies."
> You can guess why.
"So... I take I'm here to satisfy her curiosity?"
> After she hesitates, you add,
"Among other things?"
> Celestia tucks the scrolls away in some magic space.
> "That is the idea, yes. Don't worry, I'll be here to make sure she doesn't go too far."
> You wonder what will qualify as too far.
> Only one way to find out.
"Let's get this trainwreck started."
> You knock on the door to the treebrary.
> A muffled voice calls out,
> "Coming!"
> Celestia murmurs behind you,
> "She will be."
> ...
> Did you hear that right?
> Buckle down, Anon, it's going to be a wild ride.
> Twilight opens the door, mane frazzled and a pencil tucked behind her ear.
> "Good morning, Anonymous, Celestia. ..."
> The door slams, and you hear her run off.
> Celestia pushes the door open with her magic.
> "I'm sure she'll be back in a bit. Why don't we make ourselves comfortable?"
> You end up opposite Celestia at a small table.
> "And how have you been?"
> You shrug, put off balance by this new facet of her.
"Pretty good, especially lately. Work is nice, I'm making all sorts of friends."
> She smiles.
> "That's what I like to hear."
> Twilight comes clattering down the stairs, her mane tied into a ponytail with blue ribbon.
> She stumbles a bit when she sees you two at the table already, then reorients herself.
> "Good morning, Celestia, Anonymous. Oh, I said that already, didn't I? It doesn't matter, what matters is that you are here, and why are you here?"
> Celestia smiles serenely.
> "Tell her, Anonymous."
"I am here to aid you in your xenobiological studies,"
> You glance at Celestia, and finish with,
"among other things."
> Twilight glances between the two of you uncertainly.
> "Celestia, you're here to..."
> "Observe, and assist if necessary."
> "Right. Let me just get some note taking supplies and set the testing area..."
> The books on the floor rise up and file away in a haphazard fashion, while reams of paper coil and fold down to reasonable stacks.
> About twenty inkwells and even more quills scatter about the room, and a bed floats down from Twilight's bedroom to settle down in the middle of the cleared area.
> Not for the first time, you find yourself in awe of the might of unicorn magic.
> Twilight steps into a white lab coat, and clears her throat.
> "Let us begin. Please state your name, sex, and age, for the record."
> Looks like this might be a little more professional than you expected.
"Anonymous R. Le'Jion, male, and twenty five."
> After some quill scratching, she speaks again.
> "Thank you. Now, if you would disrobe, so that we can record your anatomy."
> The gleam in her eyes is anything but scientific.
> For that matter, Celestia is reminding you of the Cheshire cat a bit much for your comfort.
> It doesn't matter, this was inevitable.
> You take off your clothes without ceremony.
> Twilight pauses in the middle of her diagramming.
> "B-but my charts... the average human penis should be nearly the same size as the insertable portion of a stallion's phallus!"
> You shrug.
"I'm below average in that department."
> You have more or less come to terms with that over the past two days.
> Twilight resumes her sketch work, her gaze lingering on your crotch perhaps a bit more than is absolutely necessary.
> A few moments later, she sets down the quill and levitates a tape measure over.
> "Um, Celestia? Would you mind taking his measurements?"
> "I'd be glad to."
> She's practically purring, the metered tape surrounded in a golden glow.
> Most of the measurements are normal, height, shoulder span, arm length, etc.
> Then there's the other ones.
> "Penis length, flaccid."
> Celestia looks down at your erection.
> "Not possible at this time. Shall I give you the measurement for erect?"
> Twilight looks up from her paper, and takes in the situation.
> "R-right, let's get it while we have it."
> Celestia presses the tape to your cock, and calls out the number.
> She then slowly drags the tape along your shaft until the metered length falls off, maintaining eye  contact the entire time.
> The rest of the measurements pass a like manner, boredom interspersed with erotic tension.
> Twilight frowns.
> "I would really like to get that flaccid measurement, for a complete data set."
> Celestia chuckles.
> "I can think of a way to achieve that state. Perhaps if one of us were to give him sufficient stimulation, the refractory period would provide a window of opportunity."
> "S-sufficient stimulation?"
> Twilight rifles through her plans, and plucks out a page.
> "Phallic stimulation... yes, we can combine that with the xenophilic compatibility test."
> You think you know what that will entail.
> Twilight gets up onto the bed, then pauses.
> "Celestia, would you mind taking down my observations? I'm not sure I will be able to operate the quill while in mid experiment."
> "Of course. Anonymous, please get into position."
> You stand behind Purplesmart, the height of the bed making up the distance.
> Twilight closes her eyes, and takes a steadying breath.
> "Anonymous, i-insert your genitalia into the r-research mare's. For science."
> You are going to do so much science, you can tell.
> You prod her entrance with your cock, her soft warmth a comfort after standing around naked for all that time.
> You turn your head to see Celestia standing by, eyes wide to better take in the show.
> You slowly press inward, Twilight taking shuddering breaths as you delve into her.
> You come to a stop, fully sheathed, and the faithful student speaks.
> "As previously observed, deviation in size is observed, yet not unpleasant. The phallus shape is within acceptable bounds for providing mutual stimulation."
> Twilight shifts her weight.
> "P-procede with species specific c-copulation behavior."
> You slide your hands across her flanks and get a firm grasp of her hips.
> You can feel her trembling, and it's kinda cute.
> You begin thrusting, keeping it gentle.
> She feels amazing, wet, hot, and silky.
> The observations resume.
> "It is uncertain if a pony could break free of the human's grasp." Hnnn," Repeated pelvic thrusting seems to be the," haaaa, "main form of sexual expression."
 > You pick up the pace, slipping a hand from her hip down to fondle her hanging teats.
> She gasps at the contact.
> "Is this sta-ah~ standard in intercourse with hu, human females?"
> You slide your other hand up to her upper chest, leaning on her back to keep your balance.
"Normally the mammaries would be up here-"
> You gently squeeze her chest's taut muscles.
"-but the pony analog is sufficiently close for transference of erotic associations."
> She orgasms, walls milking your dick for all they are worth, but you aren't there yet.
> Guess she likes scientific discussion.
> She collapses, and you catch yourself on your hands, leaning over her.
> What are you supposed to do now?
> Twilight rolls onto her side, and you stand up straight.
> "Did you record that last exchange?"
> "An interesting bit of data, but are you alright?"
> Twilight climbs off the bed.
> "I'm fine, but I'm not sure I could handle another go. At least we know that ponies would be able to receive sufficient enjoyment from xenophilic activity."
> Wait, she's giving up?
> You honestly don't know how you feel about that.
> Celestia seems to share your reaction.
> "Rather than leave the test incomplete, perhaps I could collect the other half of the data?"
> Twilight perks up at this.
> "You would? I had thought that... well, if you are willing, by all means, let us continue. For science!"
> Celestia joins you in the cleared area, her eyes half-lidded.
> "For science."
> You are confronted with the royal plot, whose gravity is irresistible.
> Your hands grab a hold, kneading and spreading her cheeks.
> "The human seems to have erotic associations with the gluteal area, resulting in grasping and lifting manipulations."
> You press up against her, running your hands up her back and caressing her neck.
> Celestia arches her neck, and you whisper,
"I bet you love that I'm still coated in your precious student's juices."
> She whispers back,
> "You catch on quickly. I might make you my next student."
> Your hands snarl in her silky, flowing mane.
"I'll hold you to that."
> Celestia speaks in a normal tone,
"He enjoys dominance plays, controlling movement through mane-pulling."
> You let go with one hand, lining up your weapon with her pussy.
> She sense what you are up to and backs up, impaling herself on your rod.
> She smirks at you over her shoulder.
> You let go of her mane and seize her tail at its base, using it to lend extra force to your thrusts.
> Celestia laughs, low and sensual. Her wings are steadily stiffening, but have yet to fully unfurl.
> You slap that ass, memorizing the jiggling for future solo performances.
> "A slight tendency for sadism is observed."
> Her vaginal muscles massage your dick with the expertise of a thousand years of experience.
> If this keeps up, it will end in her victory. You have to tilt the odds back in your favor, somehow.
> You listen to your alpha instincts, and push her forward with your whole being.
> The princess's  front legs fold beneath her, and she gasps in surprise.
> This angle is much better, with her rump in the air, and you pump her with renewed enthusiasm.
> Twilight stops taking notes.
> "Celestia, are you alright?"
> The alicorn lays her head down sideways on the cool wooden floor, jostling with each of your thrusts.
> "I'm fine, he's just asserting himself, that's all."
> "O-okay, carry on."
> Meanwhile Celestia's wings are fully extended, and she is losing control of her inner efforts.
> You hook your arms under her hips and raise her up an inch or two, pounding her relentlessly.
> Her mouth opens, and her tongue lolls out, leaving a wet spot in the light dust on the floor.
> You can't keep it up any longer.
> You put your all into a final thrust, raising her back end another inch into the air as you fill her with your seed.
> The uncoordinated movement of her sheath falls away, and she clenches around your member, milking it for every drop of conquest.
> You fall to your knees, slipping out of her spasming hole.
> Celestia lets herself fall to the side, panting heavily.
> Twilight trots over, and you glimpse an odd blue glow on her tongue.
> She sits down between the two of you, and brings a hoof down to her nethers, then back to her mouth.
> That blur tongue laps up her nectar, and she swallows.
> She then takes your softening cock into her mouth, sucking off the accumulated juices.
> Lastly, she laps at her teacher's leaking flower.
"What was all that about?"
> Twilight swallows again.
> "Chemical analysis, of course. Pardon me, I have to get this all down before I forget it."
> You stare after her in bemusement.
> Celestia stirs.
> "Always the scientist, that one. That's why she is my most favored student."
"I can see why."
> After a few moments of silence, Twilight returns.
> "And now for the flaccid reading!"
 
> The research session ends an hour later, with a few more clinical gropings.
> As you schedule a time for the next session, you thank the powers that be for the mystery of pants in a pony world.