I Fucked My Mother-in-Law to Marry My Girlfriend

"Oppa!!"

The conversation—if you could even call it that—with my mother-in-law had finally ended. Yeonji, along with a woman named Yeonhee, entered the reception room. Since I'd received permission for the marriage, Yeonji was overjoyed and immediately hugged me.

"Hehehe."

"Ah!… U-um! Thank you, Mom."

My mother-in-law smiled at Yeonji's adorable behavior, and Yeonji, blushing, pulled away. She then turned to her mother, embracing her tightly and expressing her gratitude.

"Mom, thank you! I really love Oppa."

"Yes… I know… And I can tell Joohyun truly loves you too."

My mother-in-law stroked Yeonji's head as she held her close.

'A picture… a rather erotic picture.'

A daughter overjoyed about the marriage approval, and a mother pleased to see her daughter so happy. On the surface, it seemed like a beautiful scene. But with my mother-in-law's large breasts enveloping Yeonji, and Yeonji's own chest pressed against her, I couldn't help but swallow hard.

'Just a moment ago, I was doing that with my mother-in-law in this very room…'

The memory of my mother-in-law sucking my dick just minutes ago, in the same space where Yeonji now stood, filled me with guilt—and a strange, twisted sense of depravity.

'What am I going to do…'

I had agreed to become my mother-in-law's master, to train her as her sex slave, all to marry Yeonji. It was an unavoidable situation, but I couldn't deny that part of me didn't entirely dislike it. That was my current reality.

'I shouldn't be doing this with Yeonji around…'

Honestly, I hadn't been able to resist my mother-in-law's seduction. She was as much my ideal type as Yeonji. At 170cm tall, with breasts slightly larger than Yeonji's, she had a figure and looks so well-maintained that it was hard to believe she had an adult daughter. When I first saw her, I'd mistaken her for Yeonji's older sister.

'Looking at them now, their styles are quite different, except for their chests and looks… Do I have a thing for big breasts?'

The height difference between mother and daughter was striking, and while their faces were similar, the vibes they gave off were worlds apart. The only thing they truly had in common was their large chests. I wondered if I'd been captivated by that.

'Come to think of it, this woman is quite…'

I didn't know much about the woman named Yeonhee, but she stood quietly beside us, dressed in a sharp suit and skirt. Though not as busty as the mother-daughter duo, her chest was still sizable enough to catch my eye. I couldn't help but stare, and when our eyes met, I quickly looked away.

"Ah, I'm late with the introductions. This is Yeonhee. My daugh…"

"Hello, Joohyun-nim. I am Lee Yeonhee, the exclusive secretary for the Madam and the young lady."

Before my mother-in-law could finish, Yeonhee introduced herself with a professional tone.

"Hello. I'm Lee Joohyun… I look forward to working with you."

"Yes, Joohyun-nim."

Yeonhee's slightly cold demeanor made her seem like the perfect fit for her role as a secretary.

"Yeonhee Unni! Really!"

Yeonji pouted slightly at Yeonhee's formal introduction, and my mother-in-law also wore a faintly bitter expression. But the secretary didn't seem fazed.

"Then, I'll excuse myself for now as I have work to attend to. Please let me know if you need anything."

With a dignified bow, Yeonhee turned and left.

"Haa… I'll tell you more about Yeonhee later."

"Unni…"

Yeonji looked a little lonely but quickly returned to her cheerful self, as if this wasn't unusual.

"Then, Oppa, let's put you in the room next to mine!"

"No."

"Huh? Mom?"

The mansion had plenty of empty rooms, so any would have sufficed. But Yeonji, wanting to be closer to me, suggested the room next to hers. My mother-in-law, however, firmly refused.

"You're not married yet. Besides, you're still too young to get married right away. I'll allow you to live together, but the formal ceremony will have to wait until after you graduate. Keep that in mind."

"Uuu… Okay, Mom…"

It might have sounded strict, but my mother-in-law wasn't wrong. I was in my mid-twenties, so it didn't matter much, but Yeonji was still a college sophomore. Even if we married immediately, it wouldn't be a problem, but she was still young, so postponing the ceremony made sense.

'But why the room…?'

We weren't married yet, but we were a couple who would share a room in the future. It wouldn't have been strange to give me the room next to Yeonji's, but my mother-in-law was adamant.

"I've allowed the marriage for now, but honestly, I don't know much about Joohyun yet… I'll keep him in the room next to mine and observe him."

'So that's the plan…'

My mother-in-law, who wanted to be trained by me, had made excuses to Yeonji. In reality, she wanted me in the room next to hers so she could easily approach me every night.

'Look at that gaze…'

My mother-in-law glanced at me with a lewd smile, hidden from Yeonji. It seemed I couldn't escape her grasp.

'Well, there's no other way for now…'

For someone who'd lived an ordinary life, training my mother-in-law was a serious moral dilemma. Just being in the same space as Yeonji made my heart ache, but I had no choice but to go along with it for now.

'At least she's not acting lewd in front of Yeonji…'

My mother-in-law, who had been bowing and serving me as her master moments ago, wasn't showing that side of herself in front of Yeonji. That was a small relief.

"Then, I'll guide Joohyun… Yeonji, you can go to your room and do your homework."

"But I should be the one to guide him…"

"If you do it, you'll just get lovey-dovey and won't show him around properly."

"Uuu… Okay… See you later, Oppa."

"Huh?… That Yeonji too…"

"Yeonji, go upstairs quickly."

"Yes…"

As soon as Yeonji left, my mother-in-law's demeanor shifted.

"Now it's just the two of us… Master♥"

The moment Yeonji and the secretary were out of sight, my mother-in-law revealed her true nature.

"M-Mother-in-law… How about you guide me around the mansion now…"

"There's plenty of time for that… More importantly, it seems Master isn't satisfied with what we did earlier♥"

"T-That's…"

After seeing the busty mother and daughter, I couldn't help but get semi-erect again. I tried to hide it by politely clasping my hands, but my mother-in-law had already noticed.

Swoosh

"Ugh… M-Mother-in-law…"

Her hand casually moved toward my crotch, stroking the front of my pants. My dick grew even harder under her touch.

"Since there are no servants today… It's fine to walk around like this♥"

Zzzip

"M-Mother-in-law, wait a moment?!"

Her touch was so pleasurable that I couldn't resist. She unzipped my pants and freed my dick.

"It's truly an amazing dick, no matter how many times I see it♥"

Tap tap tap tap tap tap tap

She looked at my dick with the expression of a girl in love, her hand moving skillfully. A wave of intense pleasure washed over me.

'She's doing this as soon as Yeonji leaves… But it feels so good!'

My mind screamed at me to stop, but I couldn't resist her expert touch. I felt pathetic, but her technique was undeniable.

"It's so hard even though you already came so much earlier♥"

My dick, unsatisfied with just one or two rounds, stood at attention as if it were the first time.

"Then… I'll give you a tour of the house♥"

"I-In this state?"

"Oh my… Are you embarrassed?"

"Of course I am!"

Walking around with my dick out while getting a handjob from my mother-in-law—it would be strange if I wasn't embarrassed.

"Then, let's make it fair♥…"

Swoosh… Boing

"M-Mother-in-law!?"

She smiled, tugged at the neckline of her dress, and pulled it down slightly, revealing her breasts.

"This makes it fair, right♥"

"Gulp..... Yes…"

Her breasts, barely concealed under her dress, were now fully exposed.

'M-Mother-in-law's breasts… Her, her nipples!!'

They were like a more mature version of Yeonji's—slightly larger, with darker pink areolas and nipples. Just looking at them made my excitement grow.

"It seems Master likes them♥ Hehehe♥"

She smiled, pleased by my intense gaze, and deliberately pushed her chest forward, showing off even more.

"Even my nipples are standing up like this♥"

Flick

"Aah♥"

She flicked her own nipple, letting out a lewd moan. My dick throbbed wildly, precum leaking as her hand continued to stroke me.

"Then… Let's go♥"

"Ugh… Yes, Mother-in-law…"

In the end, I was too distracted by her seduction and her breasts to resist. I started walking around the house with her, my heart pounding from the taboo of it all. But with her lewd display and the pleasure of her handjob, my instincts overpowered my reason.

I had lost the will to resist, and as we walked down the hallway, I realized one thing for certain.

I liked breasts… I liked big, busty breasts…