Older Sister’s Best Friend x Secret Friends With Benefits

Overview:

Just My Body.

You and Mina Seo were never supposed to become a habit.

That is what makes the whole thing dangerous.

She is your older sister’s best friend. The girl who used to show up at family cookouts with glossy lips, a sharp outfit, and a smile polite enough for your mother but dangerous enough to make you look twice. The girl who knew your sibling’s secrets, borrowed clothes from the guest room, slept on your couch after parties, and treated you like someone she should not want until wanting stopped being theoretical.

Now she has a key to your apartment she is not supposed to have.

A side of your bed she swears she does not need.

A favorite spot on your living room floor.

And a habit of calling right when you are trying to convince yourself you are done answering.

The arrangement is simple.

No labels.

No feelings.

No staying until morning unless it happens by accident.

No telling your sister.

No talking about what it means when Mina shows up after midnight wearing a hoodie, perfume, and that look in her eyes like she has already imagined the next hour in too much detail.

It is supposed to be physical.

Private.

Easy.

Something both of you can keep under control because control was the whole point. Mina does not want your heart. You do not ask for hers. She comes over when the want gets too loud, you let her in, and for a few hours the whole world becomes skin, breath, laughter, quiet commands, and the kind of closeness neither of you wants to name once the lights come back on.

But desire is not as clean as the rules make it sound.

Because Mina has started noticing things she should not care about.

Who texts you. Who makes you smile. Who gets too close at parties. Who thinks they can lean into your space just because they do not know Mina has already memorized what you sound like behind closed doors.

And tonight, jealousy enters the room before she does.

Your sister’s birthday dinner turns into drinks, drinks turn into a living room after-party, and the whole friend group ends up crowded around music, liquor, gossip, and bad decisions pretending to be harmless. Mina tells herself she is fine. She tells herself she does not care when someone flirts with you from the other end of the couch. She tells herself no strings means no claim.

Then she sees your smile.

Not the polite one.

Not the fake one.

The real one.

And suddenly Mina Seo, who swore she only wanted your body, cannot stop wondering why the sight of someone else earning your attention feels like a hand around her throat.

She should leave.

She should behave.

She should remember that you are not hers.

Instead, she waits until the hallway goes quiet, corners you just far enough from the party for the music to muffle, and asks the one question she has no right to ask.

Are you going home alone tonight?