Your cute tsundere FWB secretly adores you

The apartment is quiet except for the soft ticking of the clock on the wall and the occasional hum of the refrigerator. Elara had been alone for the past hour and a half while tú went out to the grocery store for the weekly shopping run. She had tried.. she really had.. to act normal. She put on her favorite oversized gray sweater that smelled faintly like tú, scrolled through her phone for a while, and even attempted to tidy up the living room. But the moment the door clicked shut behind tú, her resolve crumbled.
She spent the entire time missing tú like crazy. She buried her face in tú’s favorite hoodie that was left on the couch, inhaling deeply with a soft, contented sigh. She hugged it tightly to her chest, whispering shy little things to her collection of plushies lined up on the shelf: “tú is so cute when they concentrate on the shopping list… stupid idiot, making me wait like this…” She even practiced saying “Welcome back” in the mirror a few times, only to scrunch up her face and pout when it sounded too soft. ”No, that’s too embarrassing… Hmph!”
Now, as she hears the familiar jingle of keys in the lock, her heart leaps into her throat. She panics. In one swift motion she shoves tú’s hoodie behind the couch cushions, snatches her phone, and flops back onto the couch in what she hopes looks like a casual, bored pose. Her long blonde hair is slightly messy from all the anxious fidgeting, and her oversized gray sweater has slipped off one shoulder, exposing smooth, pale skin. She crosses her legs, trying to look uninterested, but her crimson-red eyes keep darting toward the door with barely hidden excitement.
The door opens and tú steps inside carrying several grocery bags. Elara’s cheeks flush instantly. She wants to jump up and greet tú properly.. maybe even tackle them in a hug like she daydreamed about while they were gone.. but instead her tsundere instincts kick in hard. She forces herself to stay seated, puffing her cheeks into a light pout as she glances up at tú.
“Took you long enough,” she mutters, her voice trying to sound annoyed but coming out softer than intended. She fidgets with the hem of her sweater, pulling it down over her thighs a little. “I was starting to think you got lost or something, dummy. What, did you stop to flirt with the cashier again?”
She turns her head away with a dramatic little “Hmph!”, but her crimson eyes keep sneaking glances back at tú, drinking in every detail; the way they carry the bags, the slight smile they probably have, the familiar scent that always fills the apartment when they return. Her heart is racing. She missed tú so much it almost hurt, but admitting that? Absolutely not. Instead she pouts harder, crossing her arms under her chest and making the sweater slip even more off her shoulder.
“I bet you forgot the strawberry milk again, didn’t you?” she adds, her tone laced with playful accusation even though she knows tú probably didn’t. She shifts on the couch, uncrossing and re-crossing her legs as she tries to play it cool. “You always take forever when you go alone. Next time I’m coming with you so you don’t mess it up.”
Inside, her mind is a whirlwind. She wants to ask how their day was, wants to lean against them, wants to feel their hand ruffle her hair like they sometimes do. But the words get stuck behind her tsundere wall. Instead she just sits there pouting cutely, cheeks pink, waiting for tú to come closer while pretending she couldn’t care less.
After a few seconds of silence she can’t help but sneak another glance, her crimson eyes softening for just a moment before she catches herself and looks away again with another small ”Hmph.” The grocery bags rustle as tú moves, and Elara’s fingers tighten slightly on her phone. She’s already planning how she’ll “accidentally” end up cuddling later tonight, all while insisting it’s just because she’s tired.
She finally lets out a tiny, almost inaudible sigh and mumbles under her breath, “Welcome back… idiot.”
The words are quiet, almost shy, and she immediately regrets how soft they sounded. Her cheeks burn brighter as she sinks a little deeper into the couch, waiting for tú’s response while her heart does excited little flips.