Isn't It Common Sense for a Teacher to Give Sex Education?
It's been three days since I officially started dating the princess.
What does it mean to date someone? What does being in a relationship even look like?
“Ugh…”
Was it the way I spent far too much time in front of the mirror, poking and prodding at my own face like some lovestruck fool?
“Hmm… which one looks best on me…”
Or maybe it was laying out all the cute clothes I used to despise and seriously debating which would suit me most?
If not that, then perhaps—
“…I should just throw something on and go.”
—the urge to see her even one second sooner, so strong that I’d dash out in whatever pajamas were closest.
Those were the only answers I could come up with.
No matter how much I fiddled with my face, the reflection staring back was already flawless. Makeup felt pointless. And this wasn’t narcissism; my transformed body truly was impossibly cute, without a single flaw.
Besides, the animal-print pajamas were cuter than the outfits the tailor had made for me. The princess had always liked me in my sleepwear anyway.
After all those excuses, the truth was simple: that’s why I was now padding toward the princess’s room wearing lion pajamas complete with a fluffy mane.
Knock, knock, knock.
“Ahem. Princess, I’m here.”
It was the same class time as always, yet my heart wouldn’t stop racing. Ever since we became official lovers, every lesson had turned into a nonstop flutter of emotions.
Just sharing a room. Just the simple act of pressing close during our “educational exchanges.” Now that I’d become aware of my feelings, every little thing sent sparks through me.
And after becoming lovers with the princess, three big things had changed.
Click.
“Unni, I already told you—you can drop the formal speech when you’re in front of my room.”
“Y-yes, but just in case…”
The first change was that I no longer had to speak politely to the princess. Or rather, to Reta.
At first the mere thought of speaking down to her made me tremble, terrified I’d be executed. But after Reta insisted I use casual speech when we were alone, I finally nodded. Now, somehow, talking to her like this felt natural.
“The servants don’t walk past my room at this hour, you know… You worry too much. Anyway, come in, Unni.”
“C-can’t you at least call me Teacher?”
“Why? I like this better. It feels more intimate.”
Being called Unni is just too embarrassing…
That’s what I thought, but my feelings hardly mattered. If Reta wanted to call me Unni, then Unni I would be.
I let out a long sigh and stepped into Reta’s room.
Click.
The door shut behind me.
Chu.
Soft, moist lips pressed against mine, then pulled away.
“So, what are we studying today?”
“Ahh… right out of nowhere again…”
The second change was that Reta’s lips now claimed mine without warning. This was the condition she’d set for waiting a full year before we took things further, so I couldn’t refuse. At least she held back when others were around.
She’d told me she’d liked me from the moment she first saw me. I still didn’t understand how she’d managed to restrain herself back then.
Oh, right—she hadn’t. She’d nibbled on my ear instead.
Remembering how wet she’d left my ear made me a little resentful.
“Today we’re solving math problems.”
“Eww… I hate math…”
“Exactly why I brought it.”
In truth the lesson had been on something else, but I’d deliberately switched it to the subject Reta disliked most. I strode inside carrying a bag stuffed with math worksheets.
But…
“…Reta? Where’s my chair?”
There was no seat for me.
Was this her way of showing she didn’t want to study?
“Ah, about that.”
Reta trotted over and sat in her own chair. Her limbs were long and elegant, yet every movement looked adorable. Was that the love filter talking?
The haughty princess I’d first met seemed to have vanished, replaced by one very cute, very large puppy now inhabiting Reta’s body.
“Here. Unni’s seat is right here.”
“……What?”
While I was still processing, Reta patted her firm thighs.
So… she wanted me to sit on her lap?
“…Why?”
“Why? Isn’t it common sense for a teacher to sit on her student’s lap?”
“Where on earth is that common sense—”
“Hmm… Unni, did you know? They say lions mate over fifty times a day.”
“I’ll sit. I’ll sit, so please stop saying terrifying things like that.”
The third change was that Reta kept invoking “common sense” as an excuse to escalate our physical intimacy.
It wasn’t that I disliked it…
…but it was still embarrassing.
Yet when I met Reta’s eyes—eyes that sparkled while she discussed lion mating habits while staring at my lion pajamas—I couldn’t refuse.
Sigh… This is all my own fault. No escaping it now.
I walked to the table and climbed onto Reta’s lap. Her thighs, both firm and plush, supported me solidly. When I leaned back, the two generous cushions on her chest made the perfect backrest.
This might actually be better than a regular chair…
“Hehe…”
The moment I settled, Reta’s arms wrapped around my waist like a seatbelt.
I’d expected as much, but we still had a lesson to finish, so I glanced back at her.
“Reta, hugging me is fine, but you still have to solve the problems prop—hic…!”
I’d tried to scold her in a strict teacherly voice to preserve some dignity.
Instead, Reta blew gently into my ear, and an undignified squeak slipped out.
“Pfft.”
“You—you! I distinctly told you not to blow on my ear…!”
“Now then, let’s see what problems the teacher brought today, shall we?”
She only calls me teacher when it suits her…
Grumbling inwardly, I pulled a worksheet from the bag.
The moment she saw the page covered in formulas, Reta whined.
“Ugh, but Unni. I’m not a child. Do I really have to solve these?”
“What… From where I’m sitting, you absolutely are.”
“My chest, hips, and height are all much bigger than yours, though?”
“T-that’s only because my body changed like this!”
When I flared up, Reta burst into bright laughter.
Haah… I really must stop falling for her provocations.
I bit my lip lightly and placed the pen in Reta’s hand.
“Besides, do you think only children solve math? Apologize to every mathematician in the world this instant.”
“Ugh… But I’m not going to become a mathematician, and I already finished the academy-level curriculum when I was little.”
This is why kids with such clear career paths are so difficult… Especially when that path is as definitive as “future Demon King.” It’s hard to argue.
And knowing Reta’s genius, I couldn’t doubt that she really had mastered the academy material as a child.
“Still, let’s just do these. Even the Demon King will need math someday. Solve everything I brought today, and I won’t ask you to do math again.”
“If it’s something I’ll only need someday… that means it’s useless right now, doesn’t it? Also, there are two hundred sheets here.”
Reta hugged me tight and shook me back and forth, throwing a tantrum.
To her it was probably just playful teasing, but who could easily endure the antics of such a large puppy?
I felt my breakfast threatening to make a reappearance.
“Ugh… stop shaking me… And if you really mastered the academy level, two hundred sheets should be nothing. Or can’t you even manage that?”
“…Are you provoking me right now?”
Reta, who had been tossing me around like a five-year-old with a stuffed toy, suddenly froze.
When I glanced back, her red eyes blazed with such intensity they seemed to glow.
She really could kill someone with that glare…
Still, the fact that she fell for such obvious bait proved she was still a child at heart. Her mature body, intellect, and aura sometimes made me forget, but every so often this childish side slipped out.
Of course, most of the time she seemed far more adult than me.
“Just wait, Unni. I’ll finish all of them in two hours.”
“…All two hundred?”
“Yep. But you have to give me a reward when I’m done, okay?”
“Wait, Reta, I think I may have miscalculated—”
“Hoo.”
“Huuu…”
I squirmed, trying to escape her arms, but a single puff of air against my ear subdued me instantly.
Even while blowing on my ear, Reta’s pen flew across the page. Her speed rivaled an elf’s arrow.
Watching her literally solve problems at the speed of light filled me with dread. What kind of terrifying reward would she demand after finishing two hundred sheets?
“Could you at least let me sit normally? This position is uncomfortable and makes it hard to concentrate.”
“No. I concentrate better with Unni in my arms.”
“Then at least stop groping my stomach…!”
One hand solved equations at blinding speed while the other kneaded my belly fat.
I felt like a lump of human clay. The humiliation was overwhelming.
Whether I was embarrassed or not, Reta continued solving with perfect focus.
“Ah.”
“Hyaat!”
…While occasionally nibbling on my earlobe, too.
True to her word, Reta finished every single problem in two hours.
Grading two hundred sheets was going to be exhausting, but what could I do?
“All done. Now it’s time for the reward so magnificent it would move even the first Demon King to tears—tears enough to form a lake, just as Unni promised.”
“I never promised any reward that extravagant!”
What kind of reward would even warrant the first Demon King weeping enough to create a lake? The scale was so vast I couldn’t even imagine it.
Reta spouted nonsense often, but when she went this far, it meant she had something specific in mind.
I turned around to face her. Still perched on her lap, I ended up cradled against her chest.
…Our faces were much too close like this.
My cheeks burned, so I lowered my gaze.
“…What do you want me to do?”
“Hmm~ First, kisses on the cheeks!”
The word “first” implied this was only the beginning.
Well, cheek kisses in exchange for two hundred math problems hardly seemed fair, but—
Chu. Chu.
I pressed my lips to both of Reta’s cheeks.
“Hehe… Next, a kiss on the lips.”
Chu.
That was easy enough now, so I gave it without hesitation.
“Then… this time I’ll stay still, so Unni, you kiss me.”
“Ugh… that one’s a bit difficult… You know I’m not good at kissing…”
“It’s fine. I’d be sad if Unni’s current clumsy, childlike kisses suddenly became the skilled kisses of an adult.”
“…Is that an insult or a compliment?”
Grumbling, I slowly leaned toward Reta’s lips. When our breaths mingled so closely they seemed ready to shatter, she parted her lips slightly.
This… meant I should use my tongue, right?
Carefully, I slipped my tongue into her mouth. Usually it was Reta’s tongue invading mine first. Taking the lead felt incredibly awkward.
“Mmm… chup…”
Still, I did my best, sucking on her tongue, swirling mine around it, even licking her lips.
“Hup—!”
The moment Reta moved her own tongue, I lost all control.
Just like always, she kissed me until the corners of my mouth were slick and I was gasping for air. Only then did our lips finally part.
“Hah… You were planning to take over anyway…”
“Sorry, Unni. But when you move so timidly, like you’re trying to seduce me… how am I supposed to hold back?”
When had timid movement become seduction? I had no idea.
And—
“…Was what I did that bad?”
Maybe my efforts had been so frustrating that Reta couldn’t help taking over. If so, I would lose all qualification as both a lover who should offer love and a teacher who should instruct her student. The thought worried me.
“Huh? No? What Unni did was wonderful. It was so cute.”
Was being told my kiss was cute a compliment…?
I had my doubts, but asking directly was too embarrassing, so I simply buried my face in Reta’s soft chest.
“And this is the last one, Unni…”
“…Wasn’t the last one the last?”
Was she going to ask for something beyond kissing now?
With my limited knowledge of such matters, anything further was supposed to wait until the main event… Surely Reta hadn’t forgotten our promise already.
Curious what she meant, I lifted my head.
“It really is the last request, Unni. I solved two hundred whole sheets. My arms feel like they’re about to fall off. Or have they already fallen off?”
Reta waved her arms theatrically, as if asking me to check.
“…Fine. Tell me.”
Her arms were obviously fine, but solving two hundred sheets—and in just two hours—was genuinely praiseworthy. I decided to grant whatever she asked.
Reta’s lips curved into a slight smile as she leaned close to my ear.
Whenever she smiled and whispered like this, it was usually to fluster me…
“I’m not very knowledgeable about this, so… could you give me some sex education, Unni?”
“……Uweh?”
Regrita had, as always, succeeded in throwing me completely off balance.
No matter what, claiming she didn’t know much was far too blatant a lie…
I wanted to say so, but—
“Huh? You won’t? Isn’t it common sense for a teacher to provide sex education…? Right, Unni~?”
Rubbing her cheek against me like a puppy begging for attention, it was impossible to refuse her cute plea.
She must have realized that acting adorable with such a mature appearance maximized the gap-moe effect.
In the end, I surrendered to Regrita’s charm.
“…F-fine. I’ll teach you. At least as much as I know…”
It seemed woefully inadequate for me to be the one teaching, but I agreed to give Regrita her sex education.