A/N: Okay! So this is my first ever published fanfic and also attempted sin fic, so I apologize if it was bad. But hey, I tried ¯\_(ツ)_/¯ ALSO, characters may have been wrongly described as I haven't started on any of their routes and this fic was written purely based on my understanding from spoilers I've seen. So I guess its not-so-spoiler free? Leave a review or fav if you like it! That helps a lot with my motivation. :) With that being said, enjoy the sin~

PS: Smex with Saeyoung in the next chapter.

Saeran had admitted it himself that he wasn't interested in women, and surely he wasn't seeing as no woman had ever caught his eye let alone his heart. It is for that reason he just doesn't comprehend the never-ending shower of love and affection between you and his twin brother, Saeyoung.

It's been more than a month now since the three of you had started living together, and dare he say it hasn't been the most pleasurable experience ever. Why? Well for one, that poor boy's been suffering from sleep deprivation due to both of your very active sex lives and how loud the both of you can be, especially at night. As if that wasn't bad enough, you two seem to like getting it on shamelessly in places other than your bedroom. Saeran shuddered at the thought. He'd never forget the day he walked in on you two fucking on his bed with wanton noises hanging thick in the air, not to mention the times when you'd suck Saeyoung off while he's busily hacking. "Goddamn you stupid couple!" was what Saeran would usually shriek before storming up to his room and slamming the door shut, feeling mortified.

But sexy times and kinkiness aside, he could see that his twin genuinely cares for you, and is oh so deeply, madly in love with you. The last time he's seen Saeyoung showing this great amount of concern to anyone was back in the days during their broken childhood, and said concern is directed to none other than Saeran himself, and only him, because he was the only one Saeyoung had and likewise, Saeyoung was the only one he had.

Still he couldn't exactly get his head around about what his brother sees in you. What about you that makes his heart flutter, or the things you say that never fail to get him all flustered. Sure he had thought of doing inappropriate things to you before, but only with the intentions of using it as a threat to manipulate his brother into doing things his way.

Well….he thought, a sudden mischievous grin spreading across his face, guess I'd just have to find out for myself then.

Turning the doorknob as quietly as he can, Saeran poked his head out through the slightly ajared bedroom door and quickly scanned the surroundings for any familiar figures. His gaze landed on the computer chair, expecting to see his twin busily typing away with crushed cans of Dr. Pepper scattered messily around his desk, but only to be greeted by complete vacancy along with the dim glow emanating from the computer screen.

Presuming that his brother mostly likely hadn't been back yet, he crept out of his room and made his way to yours. With fingers crossed, he opened the door with one swift turn; and to his luck, spotted only a solitary female frame in the soft cushions of the bed, fast asleep. He smirked as he closed the door with one soft click before carefully striding over to your sleeping figure.

The room was virtually pitched black; the only thing that was keeping him from tripping over himself was the faint moonlight seeping in from the windows, illuminating the room ever so slightly. When he finally reached you, he climbed into bed slowly and gingerly; careful not to wake you up. With your back turned on him, he scooped up several strands of your hair, gently kissing them then softly dropping them back over your shoulder. The ticklish feeling of his fingers gliding over the skin on your arm jolted you awake. But before you could as much glance over your shoulder, Saeran nestled his face into the crook of your neck, inhibiting you from doing so.

"Mmm…Saeyoung…" you hummed as his teeth found your skin, gently nibbling on it.

Hearing your vulnerable voice like that got him feeling confused. Was it perhaps the feeling of excitement, maybe? Nah…it can't be, he thought as he continued suckling on your skin, his hand running down your waist and then bringing it back up to grab your breast, earning a yelp from you in response.

He didn't know where exactly he was going with this, but one thing's for sure that he wouldn't be stopping anytime soon. You were practically defenseless next to him and it made him want to test the waters to see how far he could take this; driving him into teasing you all the more. Next thing you knew, Saeran was on top of you and your wrists were tugged above your head, pinned firmly in place.

"Ahh!" you flinched slightly at the pain from his strong grip; you could tell that he was being rougher than usual, not that you were complaining though. Even as he hovered above you, the only thing you could make out, as far as the faint moonlight allowed you to see; was the dim scarlet lining on the silhouette of his hair. And boy was Saeran glad to have his hair dyed back to its original color for had it not been the shadows masking the dissimilar features— albeit rather insignificant- you would have been able to tell that the man on top of you right then, is in fact not your boyfriend.

"Saeyoung…mmm…what are you doing…" you managed to mutter in a sluggish state of mind.

Even in the dark you could feel the edge of his lips curled up into a smile as he takes in a good view of your helpless form. I guess your taste in women isn't that bad after all, brother. Ignoring you, he used his free hand to undo the zip to your jacket; or rather Saeyoung's jacket and was unsurprised to see that apart from your panties, you were completely exposed underneath. He knew for a fact that you loved using dirty tricks like these to lead Saeyoung on, sometimes even going as far as walking around the house with a short skirt without panties on.

He proceeded to grope your breast again, leaning over to whisper into your ear, "you naughty little girl..." You whimpered against his touch and lolled your head back as he hungrily takes a nipple in his mouth, sucking it hard.

"Sae..ah..young…ahhh," you moaned as his hand now skimmed across your belly then to your thigh. Clearly amused with your response, he then gave your thigh a tight squeeze before tracing his finger against your sex, gently rubbing on your clit through the moist fabric. You let out another moan, and he hummed against your breast, sending jolts of pleasure coursing through your body. You squirmed underneath him, arching your back and propelling yourself forward as to get more of him in contact with your needy core. He seemed to have taken notice of your impatience and gave out a devilish chuckle, followed by an instantaneous pressure that was his knee, pressing down on your entrance, hard.

Your eyes rolled back, allowing lewd mewls to escape your lips without a care. What you really wanted now was for him to take you right here and right now, and the bulge on his pants told you that he desperately needed you too.

Saeran was oh so ready to attack you when—


All at once the flick of a light switch could be heard followed by an immediate radiance of light filling the entire room. Startled, you instinctively propped yourself up causing Saeran to fumble backwards onto the sheets.

Whipping your head to the entrance of the room, your e/c eyes locked on Saeyoung's shocked ones, with a hint of anger and confusion within. Your heart sank when you finally registered the whole situation and a flush crept onto your cheeks.

"S-saeyoung! I-I…this isn't what it looks like!" your pulled the sheets over yourself while stumbling to speak coherently, frantically pointing at Saeran, who was now lifting himself off the bed with a slight smug, otherwise looking completely unfazed.

He didn't even bother turning to you as he showed himself out casually, but not before placing a gentle pat on his brother's shoulder, uttering an "I made her wet" victoriously on his way out.

You could almost hear something in your boyfriend shattering through his composed exterior after hearing that.

He continued standing at the doorway with his head down and you gulped, not knowing what to say.

"Babe…?" You started.

No response.

"I-I'm really sorry, I swear I didn't know that was Saeran…I-I thought it was you the whole time…a-and…" You trailed off and bit your lip nervously.

Still no response.

"Babe, are you mad-"

Finally he let out a chuckle, bringing his face up to meet your gaze.

"So…he made you wet huh?" His husky tone sent shivers up your spine and you began rubbing your thighs together for stimulation. You didn't even notice him pacing up towards you but his face was now inches away from yours, lips brushing against yours as he spoke.

"Should I make it so you would never think about doing it with anybody else ever again?"

You swallowed hard under his intense gaze, biting down on your lip with anticipation. Well let's just say you won't be walking straight the next day.

As for Saeran, if there's one thing he's learned, is that he found great pleasure in teasing you and would definitely love to do that again.