The first thing Yuta says when he sees Mark’s Halloween costume is “Holy .”

The second thing Yuta says when he sees Mark’s Halloween costume is “…” (Because the sight of Mark in a black, leather skirt and thigh highs has left Yuta literally speechless.)

“Oppa,” Mark greets, his voice pitched a little whinier and breathier than usual. “Happy birthday, Oppa.”

Behind him, Haechan pretends to gag. (He is, very appropriately, dressed as a devil.) Jaemin, who’s hanging off Haechan’s arm and looking radiant in his matching angel costume, pinches Haechan in the side and tells him he’s ruining Mark and Yuta’s moment. Haechan rolls his eyes and marches past them into the party, dragging Jaemin with him.

Flustered, Mark looks down. Yuta’s struck speechless again by the long line of Mark’s neck and the way the velvet ribbon choker he’s wearing emphasises his Adam’s apple. (Yuta wants to bite him. Yuta wants to use his teeth to bruise Mark’s skin purple. Yuta wants to strip Mark bare until that damned choker is the only thing he’s wearing. Yuta wants .)

“Hi, Yuta hyung,” Mark says, switching honorifics and still refusing to meet Yuta’s eyes.

This is unacceptable. It’s Yuta’s birthday and it’s Halloweekend and it’s a party. Mark has never looked so y and Yuta needs Mark to know this because he doesn’t think Mark does.

He reaches out, trailing his fingers across the bare skin at Mark’s waist (he’s wearing a crop top and Yuta wants to die ). Mark’s skin is warm and soft, and the breathless gasp he makes when Yuta touches him is a treasure. Yuta snakes his arms around Mark’s body so he can interlink his fingers behind Mark’s back and pull him closer.

“Hi baby,” Yuta says, silently thanking their two centimetre height difference when it forces Mark to raise his head to look at Yuta or else risk hitting his forehead on Yuta’s nose. “Have you always been this y?”

Mark blushes so deeply that Yuta can feel the skin get hotter where he has his hands up the back of Mark’s shirt.

“Thank you for the birthday wishes, baby. Are you my present?”

Mark closes his eyes, clearly embarrassed, and whines, “Ah, hyung~”

Yuta tsks through his teeth. Mark opens his eyes and looks back up at him.

“Mark,” Yuta chides, purposefully lowering his voice so Mark has to lean in even closer to hear him, “hyung?”

“Oppa?” Mark corrects immediately, breathless.

When Yuta tilts his head down and murmurs a husky “Good boy” into Mark’s ear, Mark’s whole body shudders.

“Oppa,” he whimpers, pressing forward to meet Yuta’s lips where they kiss a path from Mark’s ear down to his Adam’s apple. Yuta catches the bell of Mark’s choker between his teeth and Mark’s eyes flutter shut.

They’re seconds away from being guilty of public indecency when a slow clap starts behind them. Refusing to let go of his hold on Mark, Yuta looks over his shoulder to see his flatmate, Johnny, leaning against the wall of the entryway and looking far too pleased.

“I was going to give you a hard time for missing your birthday party,” he tells Yuta casually, “but I see you’re having your own little celebration out here. In the doorway to our apartment. The open doorway to our apartment.”

Johnny raises his eyebrows accusingly, but Yuta feels no shame. He does, however, recognize that Mark is probably quietly dying of mortification, so he stops the lazy scrape of his fingernails in patterns across Mark’s lower back and quietly asks Mark if he wants to go inside to join the party.

“It’s your birthday,” Mark reminds him, still somewhat shy from earlier. “I want what you want.”

“Don’t you know, baby?” Yuta asks cheekily. “Oppa only wants you.”

“Yah, you two!” Johnny calls out from where he’s retreated back toward the living room. “Don’t start that again!”

“Spoilsport,” Yuta hears Ten complain. “Things were just getting good!”

“That is better than ,” Lucas agrees.

Yuta feels the weight of Mark’s head as the shorter man drops his forehead against Yuta’s back. “I can’t believe I almost let you me against the wall in front of literally all our friends,” Mark mutters, sounding appalled.

“Oh?” Yuta’s intrigued. He wonders what Mark is wearing under the skirt. “Wall ? Was that where this was going?” (Yuta certainly hopes so.)

Mark pinches the back of Yuta’s neck. “You’re so mean to me,” he says.

The bell around Mark’s neck jingles ever so slightly as they walk—Mark’s chest pressed against Yuta’s back—into the common area where the rest of their friends are drinking and dancing. Mark detaches himself from Yuta to make the rounds and Yuta decides he could probably use a drink after the night he’s had.

“Your boyfriend looks amazing,” Joy, a girl Yuta vaguely recognizes from his composition class, tells him as he passes her on his way to the kitchen. “That skirt is killer!”

Yuta agrees, obviously, but his brain gets stuck at “boyfriend” and stays there.

He and Mark have only just made their relationship official, and this is the first time someone outside their immediate friend group has recognized that Mark is his boyfriend. Dorky, beautiful, y-cute Mark is Yuta’s boyfriend and Yuta wants everyone to know.

This girl barely knows them, yet she still knows enough to say that Mark is Yuta’s.

Pride, hot and possessive, pools in Yuta’s stomach. He wants Mark. Right. Now.

He’s across the room and has his hands on his boyfriend in an instant, relishing Mark’s squeak of surprise when Yuta’s cold hands sneak around his waist and up his shirt again.

“I’ll leave you two to it,” Doyoung says, looking between Mark and Yuta and smirking.

“It’s my birthday,” Yuta tells him, like that’s supposed to mean something.

Doyoung laughs and makes a shooing motion with his hands. “Yes, yes, I know. Happy birthday. Don’t do anything I wouldn’t do.”

“Doyoungie is !” Ten yells from across the room. “Don’t listen to him. He’ll do anything!”

“Hyung!” Mark says reproachfully, honestly a little shocked. Doyoung and Ten just laugh at him. (Though Doyoung does take the time to flip Ten off.)

“You’re my boyfriend,” Yuta tells Mark wonderingly once they’re alone. (Or, at least, as alone as you can be when you’re in a room full of people.)

“Yes?” Mark responds, confused by Yuta stating the obvious.

“And also my birthday present,” Yuta says.

Mark’s cheeks flush the same pretty pink as his t-shirt. It’s almost too much for Yuta’s heart.

Still: “And also your birthday present,” Mark confirms. “Do you like it, Oppa?”

Yuta tightens his grip on Mark’s waist almost involuntarily. “My baby’s so pretty for me,” he purrs. “Can Oppa take Baby to his room to show Baby just how much Oppa likes his present?”

Mark nods and bites his lip. It’s baby doll pink and a little shiny, and Yuta’s going crazy trying to figure out what flavor of lip gloss it could be. He is leaning down to kiss Mark and find out when they get interrupted. Again.

“You two are gross,” Haechan catcalls.

“Get a room!” Taeyong agrees loudly.

Yuta drags his attention away from Mark for just long enough to yell “I’m trying!” before he marches toward his bedroom, pulling his boyfriend behind him.

When they get to Yuta’s room, Yuta leads them to sit on the bed and catches Mark smiling at him, his eyes sparkling with amusement.

“The world is out to you today, isn’t it?”

“And on my birthday, too!” Yuta pouts. (Mark thinks his boyfriend is ing adorable.)

“Technically your birthday was yesterday,” Mark corrects, moving to sit cross-legged opposite Yuta as he talks.

“Then why the birthday present?” Yuta asks him teasingly.

“I wanted to be y,” Mark admits a little bashfully. “And I wanted Oppa to think that I was.”

“Mark,” Yuta says, flabbergasted. “Baby. Have you seen yourself? You’re gorgeous!”

Mark twists the hem of his skirt around his fingers then looks up at Yuta through his eyelashes and says, “You really think so?”

In one swift move, Yuta grabs Mark by the thighs and pulls him into his lap so that they’re sitting face to face. It’s hot that Yuta can manhandle him like that, and Mark says as much.

“Thanks, baby,” Yuta says. He cups Mark’s face and runs his thumb over Mark’s lips. “Oppa told you he’d show you how pretty you are, right?”

Mark nods and swallows, making the bell on his choker jingle. Yuta hums appreciatively and brings his thumb to his mouth to taste the watermelon sweet of Mark’s lip gloss.

(What a y boyfriend he has. What a good birthday this is turning out to be.)

“Now,” Yuta asks, bending down to place his lips at Mark’s throat and moving to slide his fingers under the waistband of Mark’s skirt, “where we’re we?”

------------------

I blame this entirely on three things:
1. Mark Lee’s clear and obvious oppa kink
2. Yuta’s birthday happening less than a week away from Halloween
3. This: https://archiveofourown.org/works/16211096

Also, it’s never said, but Yuta’s dressed like a vampire (of course). Mark’s a kitten of sorts but he got tipsy pregaming and lost his ears on his way to the party.

His outfit inspiration (if someone wanted to bless me with fan art of this Mark, I wouldn’t say no...):
- Shirt: https://i.pinimg.com/236x/7d/04/d6/7d04d62ecea3d3dd047068f52db885e9.jpg
- Skirt and thigh highs: https://i.pinimg.com/originals/b7/7e/72/b77e722c2dfba9489df79fd796240fd1.jpg
- Choker (except black and velvet): https://ae01.alicdn.com/kf/HTB108uPPFXXXXaKXFXXq6xXFXXXN/Tokyo-Mew-Mew-Ichigo-Momomiya-Cosplay-bell-necklace.jpg