The rest of the afternoon dragged by. Mia stayed by the pool in her tiny black bikini, laughing at Jake's dumb jokes, sipping lemonade, and pretending not to notice how Ethan's eyes kept finding her. Every time she stretched languidly on the lounge chair, letting the sun kiss her barely-covered skin, she felt his gaze-like a slow caress across her breasts, her stomach, the smooth curve of her *ss when she rolled over.  

Sarah stayed glued to his side, touching his arm, kissing his shoulder. Mia smiled sweetly through it all, twirling a strand of damp hair around her finger, occasionally "accidentally" brushing her foot against Ethan's calf under the water when they were all splashing around.  

"You're awfully quiet today, squirt," Ethan had murmured once when Sarah went inside for sunscreen. His voice was low, teasing, but his eyes had darkened as they traced the way her wet bikini top clung to her hardened n*ppl*s.  

Mia had only shrugged, biting her lower lip innocently. "Just enjoying the sun, Ethan. Why? Am I distracting you?"  

He had chuckled, but the sound was rough. "Why would you distract me?"  

Then Sarah had returned, and the moment shattered.  

By evening, the group had moved inside. Jake ordered pizza, they watched a movie, and the two couples cuddled on the big sectional while Mia sat curled in the oversized armchair, knees tucked up, pretending to scroll on her phone. 

She had changed into soft sleep shorts and a thin camisole-no bra, the fabric thin enough that the cool air kept her n*ppl*s tight and visible if anyone bothered to look. Ethan did. More than once.  

Around eleven, Jake and his date disappeared upstairs with barely a goodnight. Sarah yawned dramatically and tugged Ethan toward the guest room at the end of the hall-the room that had basically become his over the years because he was family. "Come on, babe. I'm tired."  

Mia waited ten minutes, heart thudding, before she stood. She told herself she was just going downstairs for a glass of water. That was all.  

The house was quiet except for the low hum of the air-conditioning. Barefoot, she padded down the hallway toward the stairs. Ethan's door was slightly ajar-probably from when Sarah had pulled him inside in a hurry. Soft light spilled out, along with sounds that stopped Mia cold.  

A low, feminine moan. The unmistakable rhythmic creak of a bed.  

Jealousy slammed into her so hard she had to brace a hand on the wall. Her feet moved before her brain caught up. She crept closer, breath shallow, until she could peek through the narrow gap.  

Ethan's room was dimly lit by the bedside lamp. Sarah was on all fours in the center of the big bed, back arched, blonde hair spilling over her shoulders. Ethan was behind her, completely naked, his powerful body gleaming with sweat. One large hand gripped her hip while the other fisted her hair, pulling just enough to make Sarah gasp.  

He was hammering into her-deep, steady thrusts that made the headboard tap softly against the wall. Mia could see everything: the way his thick c*ck disappeared between Sarah's legs with every snap of his hips, the slick shine of her arousal coating him, the way his muscles flexed and bunched across his back and *ss.  

"F*ck, you feel good," Ethan growled, voice low and rough in a way Mia had never heard before. He leaned over Sarah, one hand sliding around to rub between her legs. "Come on, baby. Let me hear you."  

Sarah moaned louder, pushing back to meet his thrusts. "Harder, Ethan-yes, just like that."  

Mia's face burned. Anger and raw jealousy twisted in her chest like a knife, but underneath it, heat pooled low in her belly. Her thighs pressed together instinctively. 

She was throbbing-her p*ssy already slick and aching, the thin fabric of her sleep shorts growing damp. She watched, unable to look away, as Ethan's pace quickened. His hand left Sarah's hair to grip both hips, pulling her back onto him harder. The wet slap of skin filled the room.  

Mia's n*ppl*s tightened painfully against her camisole. One of her hands drifted down without thinking, pressing lightly over her shorts, right where she was pulsing. She bit her lip hard to stay silent.  

Inside the room, Sarah's moans turned sharp and desperate. "I'm close-don't stop-"  

Ethan groaned, deep and guttural. "That's it. Come for me." He slammed into her a few more times, hard and fast, then buried himself deep, hips grinding as Sarah cried out, her body shaking through her orgasm.  

Mia's own core clenched in sympathy, a fresh gush of wetness soaking her panties. She was so turned on it hurt-jealousy and need warring inside her until she felt dizzy.  

Ethan pulled out, flipped Sarah onto her back, and stroked himself twice before coming with a low curse, thick ropes landing across her stomach and breasts. Sarah laughed breathlessly, reaching up to pull him down for a kiss.  

Mia stumbled back from the door, chest heaving. Her legs felt weak. Mia was angry-so f*ck*ng angry that it was Sarah in there getting what she had wanted for years. But more than anger, there was a fierce, possessive determination settling in her bones.  

She would make him see her. She would be the one who made his breath catch, who made him lose control, who gave him that pleasure next. Not Sarah. Not anyone else. Her.  

Quietly, Mia retreated to her own room, closing the door with a soft click. She leaned against it, breathing hard, one hand slipping inside her shorts before she could stop herself. Her fingers found her swollen, dripping folds and circled her cl*t. 

The image of Ethan-sweaty, powerful, thrusting-played behind her closed eyes. She came fast and hard, biting her pillow to muffle the whimper, but it wasn't enough. It only left her hungrier.  

When the aftershocks faded, Mia lay on her bed staring at the ceiling, skin still flushed, heart racing with fresh resolve.  

Tomorrow she would turn up the heat. A little more skin. A little more "accidental" closeness. Innocent touches that lingered just a second too long. She would smile sweetly and call him by name in that soft voice she knew affected him. She would remind him, without ever saying it outright, that she wasn't his "little sister" anymore.  

And when the moment was right, when Sarah was distracted or gone, Mia would make sure Ethan couldn't look away. Couldn't pretend. Couldn't stop thinking about her.  

She smiled into the darkness, fingers still lightly teasing between her thighs.  

Two weeks. Plenty of time to seduce her brother's best friend completely.  

Game on.

The next morning, Mia padded downstairs barefoot, the hem of her oversized sleep shirt brushing the tops of her thighs. The thin cotton had ridden up during the night; one wrong move and the curve of her bare *ss would flash anyone who looked. She didn't fix it. 

The house smelled of fresh coffee and toast, normal sounds drifting from the kitchen-Jake's low laugh, the clink of mugs, Sarah's bright voice asking for oat milk. Everything was ordinary. Everything exactly as it had been for years.

She stepped into the doorway.

Ethan stood at the counter in nothing but gray sweatpants slung low on his hips, back muscles shifting as he poured coffee.

 The waistband dipped just enough to show the sharp V of his lower abs. A small red mark-Sarah's mouth, probably-faded on his shoulder. Mia's stomach tightened, but she kept her face soft, sleepy, innocent.

"Morning," she murmured, voice still husky from sleep.

Three heads turned, Jake's date had already left in the morning. Jake barely glanced up from his phone. "You're up early."

Sarah offered a polite smile, stirring her coffee. "Hey, Mia."

Ethan's hand paused mid-pour. His dark eyes flicked over her-lingering on the way the thin shirt clung to her breasts, the hard points of her n*ppl*s clearly visible beneath the fabric, the long expanse of bare legs. He cleared his throat.

"Morning, little sister."

The words should have stung. Instead they sent a secret spark straight between her thighs. Mia smiled sweetly and walked past him to the fridge, close enough that her arm brushed his bare side. Warm skin. Solid muscle. She reached for the orange juice, rising onto her toes so the shirt hem lifted another inch, revealing the lower curve of her *ss and the fact she wore no panties.

She felt his stare like a physical touch.

"Sleep well?" she asked lightly, turning with the carton in hand. She leaned back against the counter opposite him, letting her thighs part just slightly as she poured herself a glass. The cool edge of the counter pressed against her bare p*ssy; she was already slick from the memory of last night.

Ethan's grip on his mug tightened. "Yeah. You?"

"Mmm. Had some... interesting dreams." She took a slow sip, letting a tiny drop of juice escape the corner of her lips. It trailed down her chin. She caught it with her fingertip and slipped the finger into her mouth, sucking gently, eyes half-lidded.

Sarah was chatting with Jake about weekend plans. Neither noticed except Ethan. His jaw flexed. He shifted his weight, and the front of his sweatpants twitched, the soft fabric doing nothing to hide the growing outline beneath.

Mia set her glass down and stretched, arms overhead, back arching. The shirt rode all the way up, flashing the smooth, bare skin of her lower belly and the shadowed hint between her thighs before she lowered her arms again. "God, it's already so hot. Maybe we should all go swimming again later."

Jake grunted. "Sure, whatever."

Ethan's voice came out rough. "You planning to wear that same tiny thing from yesterday?"

Mia tilted her head, pretending to think, one finger tracing the neckline of her shirt, pulling it down just enough to show the upper swell of her breasts. "Maybe. Or maybe something even smaller. What do you think would look better on me, Ethan?"

Sarah laughed, oblivious. "You two and your sibling teasing. Cute."

Ethan didn't laugh. His eyes had gone dark, locked on the way Mia's n*ppl*s strained against the thin cotton. He took a slow sip of coffee, but his knuckles were white around the mug.

Mia pushed off the counter and walked toward the pantry, hips swaying with each step. She passed so close behind Ethan that her breasts brushed the bare skin of his back. Just a whisper of contact. Enough to feel him tense.

"Oops. Sorry," she whispered, breath warm against his shoulder blade.

He didn't move or speak.

She reached for the cereal on the top shelf, rising onto her toes again. The shirt lifted fully this time, baring her entire *ss to the room-round, smooth, the cleft between her cheeks clearly visible. She stayed like that a second longer than necessary, pretending to struggle with the box.

Behind her, Ethan's breathing changed-shallower, heavier.

When she finally turned with the cereal in hand, his gaze snapped up from where it had been fixed. A flush crept up his neck. The front of his sweatpants was now unmistakably tented, the thick ridge of his c*ck pressing insistently against the fabric.

Mia's pulse thrummed between her legs. She was soaked, thighs slippery, cl*t aching from the thrill of his stare. But her face stayed sweet, almost shy.

"Want some?" she asked, holding up the box, voice light as air.

Ethan's eyes met hers. Something raw flickered there-hunger, conflict, heat. For a moment the kitchen felt too small, the air too thick.

"Yeah," he said, voice low. "I want some."

The double meaning hung between them like smoke.

Sarah stood, stretching. "I'm gonna jump in the shower quick before we figure out the lake or whatever. You coming, babe?"

Ethan nodded once. "Be up in a sec."

Jake headed toward the garage, phone already at his ear. "I'll be messing with the jet skis. Don't burn the house down."

The front door clicked shut behind him. Sarah disappeared upstairs, humming and the kitchen fell quiet.

Mia set the cereal down. She walked around the island until only a couple of feet separated her and Ethan. Close enough to smell coffee and warm skin on him. She looked up through her lashes.

Ethan's hand flexed at his side. He glanced toward the stairs, then back at her. His gaze dropped for a split second to the hem of her shirt, to where her n*ppl*s pressed against the thin cotton, before he looked away again.

Mia reached up as if to fix a strand of his messy hair, letting her breasts brush lightly against his chest through the fabric-one soft, accidental press. Her n*ppl*s dragged across his skin.

Ethan inhaled sharply but said nothing. His body stayed still, almost rigid.

Footsteps sounded on the stairs above.

Sarah's voice floated down. "Ethan? You still down there? Can't find my bikini top."

Ethan stepped back, rubbing the back of his neck. "Coming."

Mia stayed where she was, cheeks warm, thighs pressed together against the slick heat between them. She picked up her glass of juice like the morning was perfectly ordinary.

"Better go help her," she said softly, smiling.

Ethan paused at the bottom of the stairs, one hand on the railing. He glanced back over his shoulder. His eyes moved over her once more-sleep shirt barely covering anything, n*ppl*s tight, legs bare-before he turned and headed up without another word.

Mia let out a slow breath, fingers curling around the counter edge.

Her heart still raced. The ache between her legs hadn't eased. But she had seen the way his sweatpants had tightened, the way his hand had flexed like he didn't know what to do with it, the way he had looked away a little too quickly.