Button had a feeling of excessive warmth. He tried to toss off the blanket and then startled fully awake when he bumped his leg on a hoof.

Sweetie Belle had been spooning behind him. This is not good. She promised she'd go home last night. She zapped my spunk away, kept playing. I asked her to go, and she said she'd just finish the level, then head home. Should have held out for a Pinkie promise. Damn. Can I trust this girl now?

She stirred, then mumbled, then spoke more clearly. "Hey."

"Why are you in my bed?"

"… because you changed your mind?"

"I didn't change my mind."

"Then why did you pick me up and put me in your bed?"

Button rolled over so he was on the edge of the bed and he could face her. "Sweetie, I did not do that. You got in on your own. Like you promised you wouldn't."

She jerked away. "I didn't. You put me here."

"Do you seriously believe that? I wouldn't!"

"Do you seriously believe I would make that up?"

"You're the one who was hit by mind control! You asked to stick around while I hoofed off! You stayed all night when you said you'd leave!"

"It was an accident! I fell asleep while recharging my magic meter. Next thing I know, you're putting me here!"

"Did not!"

"Did too!"

Button got up and walked around the bed, just pacing. "I feel like you're not yourself these past two days."

"The 'mind control' has been in place since around two days after we started dating, not just the last two days."

He gave her a hard look and continued. "Don't try to deny the last two days have been much more intense than usual, and that the mind control is at the heart of it. Like Applejack said last night, I'm the one who's unaffected. It's up to me to make sure we don't go off the rails."

"That was a completely different problem. She didn't want to want what she wanted. I do."

Button completed his second lap and continued pacing back and forth. "Ah, but would you if you were unaffected, and will you once you're cured? I wonder if…". His eye caught the pinball machine. "It's like if your tilt sensor were broken and you're telling me to just roll the ball up the chute with gravity."

She sat up and threw her hooves up in the air. "I'm not a broken pinball machine!"

"You're crossing lines you don't mean to cross and you can't even remember doing it. I think something's in the way."

"All right. First, I want some things I didn't want before, but things like that happen all the time at this age. If we get rid of it in the future, I'll be okay with having wanted that."

"You can't know that."

"It feels like it's me, here, and it's not like I want to attack Canterlot. It's like I want to… well right at this moment I don't feel like doing anything with my boyfriend, but in general it feels like I want to do things that it makes sense for me to want to do, and I fantasize about some other things, and that's pretty much normal for a mare. I don't think I was wrong not to want it before, and afterwards I won't think I was wrong to want it now."

"Okay, but you might later think I was wrong to go along with anything you said. If I'd been affected, maybe, but I'm not. You had stricter standards, you will have those standards again, and I have had my standards all along. We're taking this in a reasonable order and pace so we don't fuck this up because I don't think there's a way in Tartarus I can find another mare as amazing as you."

She didn't catch the compliment and rejoined, "Taking it too fast is not the only way to fuck things up, Button. You've got to also trust me! I did not get in bed with you. I was going to go back home and go to sleep because I was very, very tired. So tired that I fell asleep here. Next thing I know, I'm being carried into your bed. You don't remember carrying me."

"I don't think I can carry you."

"Then what, do you think your mom did it?"

Button stopped. He took a deep breath. "Maybe. She ships us hard. If you didn't, then it was definitely her. Come to think on it, that's not far-fetched. Sorry. It didn't occur to me."

Sweetie flopped back onto the bed. "Okay. I guess I can see how it wouldn't seem like a go-to explanation. But, Button? There's a second thing."

Button's wave of relaxation snapped back into mild terror.

"I… really, really want to have sex. I'd been hoping to just get by with accelerating our schedule, but if you're determined to take it slow… How long are you thinking?"

"I really don't know. I love you, Sweetie, and I don't think it'd be right to do that with you while you're affected, unless you're stuck that way permanently."

Sweetie groaned. "I'm beginning to come around to your way of thinking."

"How so?"

"We can't have sex while I'm screwed up like this. But if I don't, I'm going to explode."

Button frowned. "Were you okay for the day after Twilight kissed you?"

"Yeah! Can we take things like normal so long as I don't make any decisions when I haven't kissed Twilight in the last day?"

Button thought for five seconds. "Normal. A regular pace. No acceleration."

"Ugh. Well, then, want to head over to the castle for my daily treatment?"

Button chuckled. "This is going to be weird. Sure."

They set out side by side. Button looked about furtively; Sweetie held her head high. "Button, this is not a walk of shame. As if there ought to be such a thing. You did good last night, all around. And we did kind of all right this morning, in the end."

Button breathed deeply and nodded. Sweetie pulled the castle door open and they slipped inside.

As Sweetie led him purposefully, Button observed, "It's very early. Do you think she's up yet?"

Sweetie shrugged. "I think it counts even if she's asleep. I don't remember how I know which room is hers, but here it is." After checking… "She's not there. Library, probably."

They headed to the library; Sweetie softly asked, "Twilight? I think we need to kiss again."

There was no sign of Twilight other than a pile of notes.

"If she left notes out like that, she's probably still here. Maybe she fell asleep in the stacks." Sweetie glanced at the header of the paper on top of the pile. "It's about this mess."

Button looked alongside. "How can you tell? It's in some kind of code."

"What? Seems to me like perfectly clear Equish."

After giving it a second look and shaking his head, Button said, "Must be a magic code tied to the thing. That's a good sign! What does it say?"

She read:

Kissing Observations:
- Frequent intergenerational kissing keeps most symptoms at bay (Rarity, Spike) (so 9 years is sufficient? 3:2 age ratio? Hoofner rule??)
- Effect of kissing lasted precisely 1 day (Me, ~~Ru~~subject 1). Can gather more data easily.
- Possible: fantasies began to leak after kiss effect lapsed
I have begun to fantasize about subject 1 and 2's fantasies, and I have a suspicion that the other new one is from subject 3. No obvious import from subject 4, though could have had overlap. Since I heard subject 1 and 2's fantasies, this could just be my thinking about them and thinking of a new one on my own. Again, easy to gather more data.

Further treatment:
- Subject 5 reported total cure after 'more than kissing' with unknown (to me; probably not affected). Over a month has passed since subject 5 last had contact with subject 0, and cure has lasted since then.
- this was definitely intergenerational.
- Subjects 4 and 6, and now 7 and 8, have had same-generation sex, no effect. 4 and 6 have kissed. 7 and 8 have not (arguably).
- if vision is a guide, kiss and immediate intergenerational sex triggered spell's release effect.
- But 5 probably did not kiss: would have already known about kiss effectiveness
- Possibly need to have one participant under dark magic so it can be broken by effect?
-- Subject 5 and partner were probably not under dark magic effect.

Experiment:
- get affected volunteers for intergenerational sex. Try each step and be sure it did not work before proceeding.
- 1 simply make contact
- 2 slight insertion
- 3 full penetration
- 4 climax
- In any case, note exact time of start. Proceed slowly, until effect is noticed. Immediately withdraw upon feeling relief. Note exact time of finish. After, monitor thoughts for possible return on following days, especially at that time each day.
- If that doesn't work, go back and ask subject 5 just what the buck she did.
- Lesbian action sufficient? Same sex kisses seemed the same as mixed-sex kisses. Affected stallions in short supply. Or could go outside circle of affected. Or make more?
-- No other leads. All previous participants

Sweetie and Button shared a look. Sweetie swallowed.

Button closed his eyes. "That last line… I… if this is the only cure we can have… I suppose it's necessary."

She swallowed again. "I'm afraid that I'll enjoy it."

"Well, don't go out of your way to make it as fun as possible unless that's necessary, but if you do end up enjoying it… all right?"

"You're okay with me just bonking somepony else but not okay with me bonking you?"

"I'm kind of resigned here. But it's all in the reason for doing it, Sweetie. So you can be yourself again."

"I know why you'd think that, I'm just impressed it sounds like you actually feel it."

"If you just did it because you felt like it, that would be very, very bad. But… it'd help if it were somepony you don't know. So far it seems like everypony is. Also, I don't know of anyone outside our age range who's a guy. It might need to be… you know."

Tempest gently cut in, "I don't know you."

They spun in alarm and found her lying on a bench at the side of the library, a magic textbook in front of her.

Sweetie frowned. "Commander Tempest?"

"I'm afraid you have the advantage of me."

"I'm Sweetie Belle, Rarity's sister. This is Button Mash, my boyfriend."

"Ah. Would you like to attempt the first experiment, at least?"

Sweetie frowned. "That wouldn't be the first experiment, since it's listed lasss… huh." Tempest had rolled to sit upright, presenting her cock. "Have you always had that?"

"Twilight spent the evening working on replacing my horn. As a warmup, she gave me… this temporary addition. Unlike the horn is to be, this is not quite fully functional - I can't get anypony pregnant."

Sweetie pumped a hoof. "I knew she could make a penis. Take that, inaccurate fantasies!"

Tempest got up. "Shall we?"

Sweetie boggled and chuckled. "Like that? Just go?"

"Foreplay is for ponies who are making love. This is curing a disease."

Sweetie glanced to Button. He soberly nodded, propelling her laughter from chuckle to a single sharp laugh, then a giggle. "I suppose. All right, doctor." She spun around and flipped her tail up.

Tempest walked closer, but stopped short of making contact. "I will stand rigidly and you may press back. You are in control."

Sweetie nodded and noted that Tempest wasn't kidding about rigidity - she seemed to be at attention, and indeed gritting her teeth. She sidled backwards and made contact.

After three seconds, Sweetie commented, "I feel the urge to push back hard. Even though I don't think we're entirely lined up. Well, now we're lined up." After ten seconds, she added, "I don't think this is working. Shall we move on to step 2?"

Tempest jerkily shook her head, and Button relayed the 'no' to Sweetie. Tempest managed to grunt out, "I'm feeling… different." An intense grimace crossed her face, then she relaxed.

Sweetie simultaneously blinked, and after a few seconds commented, "As far as I can tell, the spell's gone from me."

Tempest took a few deep breaths, "Yes. Quite."

Sweetie sighed and looked to Button. "I think it's over. For me, at least. Take a few days to be sure."

Button shook his head. "That… that was so underwhelming that I can't even feel jealous. Did you even feel it?"

Sweetie shrugged. "She barely touched me. Didn't even enter, just got lined up and that was enough."

Tempest nodded. "Good!"

Sweetie took the quill and went to the page, and wrote under the bottom line: "Tempest - Sweetie - 1st test sufficient. Start: 6:49. End: 6:50." She sighed. "All right. How about we drop by the boutique? Rarity might be wondering what happened to me."

Author's Note

Apparent grammar error is in her text, not mine. What could she have been about to say, and why did she stop?

By the way,
subject 1 = Rumble
subject 2 = Sweetie Belle
subject 3 = Luna
subject 4 = Night Light
subject 5 = Celestia
subject 6 = Twilight Velvet
subjects 7 & 8 = Twilight Sparkle, Tempest Shadow