Behind Each Other's Back (5)
So.
It was the day I heard my sister kissing Seo Woojin, through a file he'd recorded and sent.
"…What."
That was more or less my first impression.
Why on earth would he send this to me?
A karaoke track murmuring in the background, and then, for the briefest moment, the soft sound of a kiss to close it out. That was all Seo Woojin had sent. Two plain minutes. No surprise post-credits stinger—these days they aren't even much of a surprise—after the credits roll. Just two clean, unadorned minutes.
I played it again on a whim. Same thing.
A woman I took for my sister and a man I took for Seo Woojin, gently mixing tongues, and then the recording ends on her rapt little sigh. Hwaah…
…At the very end she was probably panting with his tongue still laid across her lips. Staring up at Seo Woojin with those deep-green eyes, the exact same as mine.
"……."
Anyway. Right.
So what, exactly, was he trying to do by sending this to me?
"Did he send it to the wrong person?"
Maybe he'd meant to message himself, save the file, and slipped—
…No. That couldn't be it.
Sending a recording to someone else is already a faintly annoying thing to do, and this was a recording you absolutely should not play for just anyone. He would have checked, carefully, who he was sending it to before he hit the button.
Which meant that unless Seo Woojin had done something spectacularly brainless, he had recorded it and sent it on purpose, so that I would hear it.
"…Why?"
Why, of all things, would you let me hear you kissing my sister.
If you're going to do that, at least write the reason underneath. For fuck's sake…
I rolled.
Phone still in my hand, I gave a light tumble across the bed. It was too small for a full turn—barely even half—but that was enough. All I'd wanted was to crush the fluffy pillow and blanket to my chest and squeeze some of the stress out.
Anyway. Stress slightly vented. Time to think.
Reasons Seo Woojin might send me something like that.
Showing off?
Probably not.
Surely he wasn't trying to say, look, I put what you taught me to good use on your sister…
"…Huh…?"
Wait.
That actually sounds right.
Turn it every which way, and that was still the most plausible reason. To put it shortly, it felt like Seo Woojin submitting his homework for me to grade.
Just like you taught me. At the place I went with you. Not with you. With your sister. I even got as far as a kiss. Is this good enough. …How was it, teacher. Did I do well?
…Something like that.
"……."
So they did it.
A kiss.
Seo Woojin and my sister…
Mm…
I sank for a moment into a strange feeling I couldn't refine down to any single word and spit back out. The slider on the file was already jammed against the right edge. I dragged it a little to the left.
Fwaaah. Chup.
My sister's ragged breathing, wet and sticky, cutting through the karaoke track.
Wait. Stop.
The words themselves a little passive, a little defiant, and yet so full of how much she liked it that it spilled over—my sister's voice, melted sweet.
I'd already heard the recording three or four times, but only now did a proper reaction soak all the way through my brain.
Seo Woojin had kissed my sister.
At the place I had taken him to first, Seo Woojin had kissed my sister.
…Right.
When I'd first offered to do something for him in return for the treatment, hadn't he asked me to let him practice dating my sister? Karaoke had been on that list. So the two of them taking it slow like that, on a date course I myself had recommended, was the most natural thing in the world.
And yet.
"……."
Jealousy.
That wasn't a word I was allowed to aim at my sister's boyfriend.
But this sticky, wet, displeased feeling—I didn't know what word to stick on it. In the end I forced the arrow of my thoughts to bend off to the side.
Then what about me. Me, the little sister. Me, who had only been Seo Woojin's practice partner. Me, who had only been a stand-in for my sister. What was I even supposed to say back to that recording.
"Nnngh…"
Good job?
That didn't feel right. Someone else might think it was the correct answer. I just didn't like it.
You finally did it, you frustrating bastard?
Yeah. That one felt more or less all right.
I almost tacked on something like, guess practicing with me helped, and then wiped it out of my head. Say that much and it starts to sound clingy. We hadn't even dated. I'd only been a practice partner.
Play it cool.
Having sworn that to myself, I rolled another half-turn off the bed, hooked a strand of hair out of my mouth with one finger, and started tapping at my phone.
But a moment later I held down backspace and erased every word. That still wasn't enough. I killed the screen and tossed the phone onto the blanket I'd rumpled hugging it.
My heart felt strange. Like something in it was broken. Not fatally. Just uncomfortable enough to nag. That kind of broken.
Huuu…
I pressed the heat deeper into the hands covering my face, then went out to the kitchen and wet my throat with cold water.
"……."
I didn't want to admit it, but.
Apparently…
…I was sulking.
The reason: my sister's boyfriend had kissed my sister.
And that, a little, got under my skin.
My sister had left the room.
On purpose?
No. No.
She wouldn't step out on purpose. It's not as if she was trying to set me up with Seo Woojin. I knew perfectly well it was nothing but coincidence.
"……."
…And yet, alone with Seo Woojin in a room with the door shut tight, I kept remembering the day we'd practiced kissing.
…The day we'd done sex practice.
And for no good reason, things got awkward.
What was I even supposed to say…
Unlike Woojin, who just crunched a cookie and looked mildly sheepish, I had too much on my mind. I kept my mouth shut and looked away. I wished I could be as unbothered as he was, but this was simply how I was made, so I fiddled with the board-game cards we'd just been playing.
…Haaah.
What do I do…
Part of me wanted to follow my sister out right now, claim I needed the bathroom, and slip away… But if I thought about meeting Woojin later behind her back, it seemed better to ease this awkwardness while I had the chance, so I couldn't get up.
…Not because being alone with him felt good.
Absolutely not…
…….
…Mm.
"Jiyoon."
"Ah, uh…"
I'd been sprawled there, diligently shuffling the scattered deck, when Woojin—having swallowed the last of the cookie crumbs—got there a step ahead of me.
…I was startled enough to bite my tongue by accident. He didn't seem to care.
"…While your sister's in the bathroom, there's a few things I want to ask you."
"…Things you want to ask?"
Instead, the distance between our bodies closed all at once.
When he'd come over earlier to ask if I was all right, there'd been room for about two palms between us. The moment my sister was gone, that gap became one.
No.
Less than that.
…And so his hand came down over mine. So that if he felt like it—even if my sister walked back in right now—he could grip my hand tight and not let go.
"You listened, right?"
"L-listened? To what?"
"What I sent."
"……."
"…The little 1 disappeared in under three minutes."
"Ah, that…. The recording…"
"Yeah. That."
"……."
His voice was endlessly soft. Woojin's usual tone was already low and calm, so now it tickled at my ear. But inside that voice I felt a pressure I couldn't name. As if I'd become a squirrel standing in front of a snake with its mouth wide open. That nameless pressure.
…Ah.
Probably just because we were having a secret talk behind my sister's back.
It's fine. We're only sitting a little close, and even if she suddenly kicks the door open, nothing will happen. If he just lets go of this hand, nothing will happen. It's fine…
"…I listened. To what you sent."
"Yeah?"
No reason to lie, so I answered honestly. The part where listening to it had quietly turned me on, and I'd used it as material a couple of times—that I would take to my grave. But there was no need to hide the simple fact that I'd heard it.
At that, the light smile at the corner of Woojin's mouth turned a little more shameless.
…Perverted bastard.
He really did want to hear I only did what you taught me. Did I do well, teacher?
Last time, too, when he had me on CZ and Discord while we were having se—
Ah, anyway.
I'd felt it then as well. This guy is a pervert. No question.
"You listened…. You listened…"
"……."
"You didn't say anything, so I even figured you'd just left me on read."
"…Left you on read, my ass…. Normally you can't help opening something like that, if only out of curiosity…"
"So."
"……?"
"So you listened. How was it?"
"…What?"
"Score the recording. Zero to a hundred. You never told me anything."
"……."
A pervert.
An actual pervert.
"H-how am I supposed to score something like that, you idiot…!!"
"You're the one who taught me how to kiss."
"What does that even—"
You lunatic.
You said you'd already kissed my sister—just that you hadn't had sex—didn't you? And I was clearly only going to mime a kiss with a mask on, but you got worked up, yanked my mask up over my eyes, and kissed me. And then you went and had s… sex with me anyway…!
What, because I tempted you first, now you want to say the kissing lessons were my doing too?
……I-I mean, yes, I tied my hair in a ponytail like my sister, wore those tight dolphin shorts she used to wear, and in her room, while she was gone, even copied the way she talks. For sex practice I lent him my thighs for thigh-sex, and because the friction stung I spit on his cock myself…!
But tempting him was—
"……."
A-asking me what my sister likes instead of asking her. Freezing the second he so much as climbed onto my thigh. Right up until we had sex I'd thought he was a shy virgin, and now that he's had me once he's gotten cocky and—
"…I just have to score it? How the recording was?"
"Yeah."
Fine.
I'll play along this once.
Haaah…
"…Five."
"Out of five? Or out of ten?"
"…Out of a hundred."
I matched the childish state of the male mind with an equally childish answer. Honestly, all you can tell from a recording is the sound, and even that was half-buried under the karaoke track—only clear when my sister was breathing hard. I had no idea what he expected me to grade.
"Stingy score."
"…Hmph."
"And here I thought I'd done pretty well, following what I learned."
"How am I supposed to know from sound alone, idiot."
"Still. You must've heard how happy she sounded once the kiss was over."
"……."
"She was so cute, panting and looking up at me…. …Ah. She looked just like you."
"S-shut up…"
Anyway, that ought to be enough.
I wiggled the right hand pinned under Woojin and, with my left, picked up a butter cookie—soft, crumbly—and ate it.
"Then where do I need to fix it to get past a five?"
"……?"
I'd been waiting for my sister, nibbling the cookie.
"There's stuff to fix, right. The parts I got wrong."
"…Fix…"
I dropped the fresh cookie in my hand.
Was drawn in, gently, by Seo Woojin.
Behind my sister's back. With my sister's boyfriend. I never thought a kiss thick with the sweet smell of cookies was where this was going—
"……Mmmp, chup…. Mmph…"
…when, in fact, I'd half expected it.
I let the strength slip from my body, roughly counting how long it had been since my sister left, and quietly took Seo Woojin's tongue.
"…Fwah…. …A little more aggressive than this…. Chup…. Mm…"
A few days ago, when I'd heard my sister and her boyfriend kissing. The sulk that had stayed lodged in me ever since melted, all of it.
Breathlessly.