the sound of the doorbell made donghyuck jump up from his slouched position on the sofa and run to the door to open it.

his and dahyun's parents had left the apartment earlier that morning, and now, mark had arrived, and he wouldn't be leaving for the next two weeks.

"hello, hello!" donghyuck grinned, opening the front door and seeing mark standing there with a suitcase.

"hello, donghyuck." mark smiled back.

"please come in." donghyuck declared, stepping aside so that mark could enter.

the older boy pushed his suitcase inside, allowing donghyuck to close the door behind his back.

"are you sure your parents are okay with- "

"our parents don't care, really." donghyuck rolled his eyes as he grabbed mark's suitcase and headed right to his sister's bedroom.

"wait, where are you going?" mark asked, following donghyuck closely.

"i'm putting your suitcase in dahyun's room, because that's where you'll be sleeping." donghyuck told, placing the big suitcase next to dahyun's desk before looking at mark. the boy had his eyes widened and his cheeks flushed. "what?"

"i-i... i thought i was sleeping in the guest bedroom..." he admitted.

"what?!" donghyuck exclaimed again.

"well- "

"ah!!"

both boys were surprised to see dahyun entering her room with a towel wrapped around her body and another one around her head to dry her hair.

"oh my!" mark exclaimed, closing his eyes and blocking his view with his hands.

"come on, don't hide your eyes like that!" donghyuck rolled his eyes. "there's nothing to see. dahyun is flat chested!"

"hey! stop saying bullshit!" dahyun scolded her brother. "and i didn't know mark was there already."

"y-yeah, hi..." mark smiled, his eyes still covered by his hands.

"do you mind... going out for a few seconds? just while i'm changing?" dahyun asked.

"you guys are two prudes..." donghyuck muttered before wrapping his arm around mark's waist and helping him out of dahyun's room since he still couldn't see.

once they were out, dahyun closed her door, and donghyuck brought mark to his own bedroom.

"you can open your eyes now." he declared, placing his hands over his hips while looking at mark's flushed cheeks.

"y-yeah." mark nodded, now looking at his surroundings and smiling at the way donghyuck's room was messy.

"you guys have been together for seven months, and you have never slept together?" donghyuck asked.

"no... is that a bad thing? should i have invited her to a hotel for a night?" mark questioned immediately.

"it's your sexual life, you do whatever you want." donghyuck rolled his eyes, sitting down on his bed.

"s-sexual?!" mark's eyes widened.

"oh god, you thought i was speaking about actually sleeping?" donghyuck snorted when mark nodded shyly.

donghyuck thought for a while, smirking when he heard the sound of the hairdryer in his sister's room.

"you're a 21-year-old man, right?" donghyuck asked, standing up again.

"yeah." mark nodded.

"then... you sure have already experienced being horny..." donghyuck continued, taking slow steps towards mark.

"y-yes." mark admitted, his cheeks flushing.

"and how do you cope with it...?"

mark gulped, wondering when the room had gotten this hot.

donghyuck was standing right in front of him. one more step and their bodies would be glued together.

"h-hum... w-well..." mark stuttered. he couldn't understand how donghyuck could be so confident while speaking about that.

"you jerk off, right?" donghyuck tilted his head to the side, one of his fingers curling around the collar of mark's shirt.

"hmm..." mark hummed, his eyes squinting to look at donghyuck's finger.

"and... what do you imagine while pleasuring yourself...?" donghyuck continued his questioning.

"w-w-what...?"

"do you imagine my sister?" donghyuck smirked, pulling onto mark's collar and making the older boy lose balance and fall forwards, right into donghyuck's chest.

"d-d-donghyuck..." mark muttered, standing up again.

"doesn't that make you want to know what it feels like...?" donghyuck kept going nevertheless.

"d-donghyuck..." mark gulped, feeling his trousers getting too tight for him. he didn't know what was happening. how could donghyuck have this much power over him? how could he turn him on so easily, with nothing more than words?

"...to have yourself inside of my twin sister... wouldn't that feel great...?" donghyuck whispered, his lips brushing over the shell mark's ear.

"d-donghyuck stop!" mark tried pushing the boy away to breathe.

donghyuck chuckled, looking at mark's flushed cheeks and the way he kept his legs closed.

"you sure have never thought about something as dirty as fucking my sister." donghyuck said, looking up and down at mark's ravaged state.

"i don't know..." mark lowered his head.

"well, i do." donghyuck snorted. "if i made you hard with that, it's that you haven't."

mark sighed in despair, wanting to die on the spot.

he looked so much like a fool in front of donghyuck...

at least, he was glad that this happened while being with a boy, and not with his girlfriend. this could have been even worse.

"go have a cold shower if you want to get rid of that boner." donghyuck stated, sitting on his bed again.

"h-huh?" mark blinked in confusion.

"cold shower. for your dick to go back to its normal state." donghyuck repeated his eyes falling on mark's clothed member.

this made mark shy, and the boy immediately placed both of his hands in front of his crotch aera to hide himself from donghyuck's piercing eyes.

"b-but... dahyun..." mark stuttered; his cheeks still as red as before.

"i'll cover you. don't worry." donghyuck nodded. "now go."

and so, mark headed to the bathroom, taking an ice-cold shower to get rid of his problem.

on his side, donghyuck smirked to himself. things promised to get fun if mark got horny this quick...

＃

the day passed quickly, and soon the sun had set, leaving its place for the moon to take.

donghyuck, dahyun and mark were sitting side by side on the living room couch, watching the end of a movie they had started one of the numerous times mark had been at their house in the afternoon.

dahyun yawned loudly for the nth time, making her brother tsk.

"now, shut the fuck up, will you?" donghyuck asked.

"i see my presence is much appreciated here." dahyun replied, cuddling into mark's side.

"i wouldn't mind you not being there, frankly." donghyuck muttered.

"same here." dahyun tackled back.

both stayed silent for a while after this.

"i think i'm going to go to bed..." dahyun declared before the end of the movie when she realised her eyes were closing on their own. "you're coming mark?"

"sure." the older boy nodded, standing up and following dahyun towards her bedroom.

"wait!" donghyuck exclaimed, pausing the movie.

dahyun and mark turned around, the girl having a pissed face on.

"what again?" she asked.

"hadn't mark said he absolutely wanted to see the end of the movie?" donghyuck spoke, his eyes meeting mark.

"h-huh... n- "

"don't you remember, mark?" donghyuck asked again, now glaring at the boy.

mark suddenly understood the subliminal message.

"o-oh, yeah!" he nodded. "yeah, i remember."

dahyun raised a brow at him before shrugging. "okay, well, good night. i'll surely be asleep when you'll go to sleep."

mark hummed, wrapping his arms around dahyun's waist to kiss her goodnight.

donghyuck looked carefully at the way mark's hands were placed high on the girl's back, and not on her butt – like any horny teenager would.

soon, they parted, and dahyun headed to her bedroom while mark plopped on the couch beside donghyuck.

"i told you i wanted to watch the end of the movie?" mark asked with forrowed brows.

"no, you stupid boy." donghyuck rolled his eyes. "i wanted us to have a little talk."

"oh..." mark nodded slowly. "about what?"

"you and dahyun's relationship, duh." donghyuck answered.

"oh, yeah."

"so, tonight you're going to sleep together so- "

"we're having sex tonight?!" mark exclaimed as his eyes widened.

donghyuck gasped inaudibly, slamming both of his hands over mark's mouth as soon as the words left it.

"what went through your head?!" donghyuck whisper-yelled.

"w-well... i thought... you said we were sleeping together tonight... so..."

"i meant actually sleeping." donghyuck's eyes rolled to the back of his head.

"h-how could i know...? this morning you said it meant- "

"yeah, it depends on the context." donghyuck cut mark. "now let me finish."

mark nodded.

"so, since dahyun and you will be sleeping next to each other tonight, i need to give you a few warnings." donghyuck explained.

"okay." mark gave donghyuck all his attention.

"first, no sex." donghyuck said. "i'm in the room just next to yours, and i don't plan on hearing live porn while going to sleep. understood?"

"hmm." mark nodded slowly, his cheeks becoming red again.

"new, second, sleeping. i don't want you to spend the night stressing over whatever and keeping your eyes open until tomorrow morning." donghyuck continued. "third, don't try being affectionate in your sleep, like hugging her or anything. it's very uncomfortable to sleep with your arms around someone, or having an arm poking at your rib."

"so, no cuddling." mark kept that in mind.

"yeah, eventually when you wake up tomorrow morning, but don't fuck up by slamming your hand on her breast or anything. be gentle and careful. plus, she's an ass first thing in the morning, so good luck." donghyuck stated.

"h-huh... okay. is that all?"

"no. fourth, and very important if you still want to be alive tomorrow." donghyuck showed mark four fingers. "the hair."

"the hair?" mark repeated.

"if you ever roll around the bed during the night and accidentally pull on her hair, she'll scream so loud that you'll become deaf. dahyun's hair is very sensitive, so be extra careful about that. she once dumped a guy because he kept pulling her hair on accident." dongyuck explained.

"o-oh..." mark gasped.

"yeah, so, if you don't want that to happen to you, i advice you to watch her hair." donghyuck nodded. "and i guess that's all."

mark gulped, repeating the four things donghyuck had told him in his mind.

"d-donghyuck...?" mark asked, catching donghyuck's attention as the boy had started watching the film again.

"what?"

"are you sure it's a good idea that i sleep with dahyun?" he asked. "i can use the guest bedroom, really..."

"no." donghyuck replied, looking back at the screen.

"b-but why...?" mark whined.

"first, because we don't have a guest bedroom and second, because you told my sister you would sleep in her bed tonight." donghyuck said, making mark sigh in despair.

donghyuck smiled contently at the silence that had taken over the room, making it possible for him to watch the movie in peace.

"can i sleep with you?" mark asked out of the blue, making donghyuck's eyes widen.

"you want to have sex with me?!" donghyuck gasped fakely. "that's cheating on my sister!"

"n-n-no!" mark's face became red. "i meant actually sleeping."

"no shit." donghyuck rolled his eyes.

"so...?"

"no." donghyuck replied firmly.

"but why...?" mark whined again.

"what will you even tell my sister tomorrow morning when she'll wake up with no one by her side and she'll find you in my bed, huh?" donghyuck raised a brow. "that we both have the same face and you were sleepy so you thought you had entered her room when it was actually mine?"

mark chuckled. "that's a brilliant thing to say!"

"yeah, no." donghyuck kept his cold façade on.

"but- "

"there's no 'buts' mark." donghyuck sighed, trying to hide his anger and desperation. "you'll stay in bed next to dahyun and everything will be alright. now go if you want to have a slight chance of talking to her and getting comfortable before actually sleeping."

mark sighed, standing up and walking towards the bedrooms slowly.

"and mark?" donghyuck spoke again.

"yeah?" mark turned around at lightning speed, expecting donghyuck to allow him to sleep somewhere else.

"cold shower first thing in the morning." he declared. "i don't intend to see your hard dick just after waking up."

mark flushed but nodded anyway before heading to dahyun's bedroom, leaving donghyuck alone with the movie.

the tanned male made sure mark was no longer in his sight to sigh loudly.

he pulled his phone out of his pocket, opening the 'note' app to find the bullet list entitled 'donghyuck's devilish plan to be better than mark'.

"okay, so now, step 3." he declared, drawing a tick next to the second step that had been completed. "things are about to get really good..."