"What are you doing here?"
"You invited us. Same as you do every year."
Katara tried for her most innocent smile as Zuko frowned at her. She rested her arms on the ground at the edge of the pool, cursing her luck. She loved their yearly gatherings on Ember Island; it was always great to see her friends in a place where they could just be themselves and not worry about politics or appearances. That didn't mean she couldn't use a break from them every now and then, and so she'd been ecstatic to find the little pool and waterfall hidden a few minutes' walk from the royal beach house. She should have known that Zuko would know about it. He'd been visiting Ember Island since he was a kid.
"That's not what I meant, and you know it," Zuko said, crouching down in front of her.
His face softened and some of the irritation left him, though Katara could tell that Zuko was still holding a lot of tension in his body. The corner of his mouth twitched in the way it did whenever he tried to hold back a smile, and Katara didn't try to hide hers, pushing away from the edge and swimming out to the middle of the pool.
"It's big enough for both of us."
Zuko stood and shifted from foot to foot, his eyes following her every movement, and Katara put on a show for him, diving under the water and using her bending to propel her around the pool without disturbing the surface. Hearth thudding, she swam toward the waterfall, then surfaced to beckon him over. Ten years she'd known him. Ten years, they'd been incredibly close, writing each other constantly, going out of their way to visit each other, sharing secrets they wouldn't tell anyone else, staying up well past moonrise just to enjoy each other's company. So, Katara considered herself a Zuko expert. Sometimes she liked to pretend that she knew him better than his own uncle.
"I brought snacks," she said, flashing him a bright smile.
He laughed then, pulling his shirt over his head, and Katara inhaled sharply, her fingertips tingling. She wasn't so far away that she couldn't see beads of sweat as they rolled down his chest, moving over muscles hardened by hours and hours of firebending practice. Ten years she'd known him, and for the past three, she'd started to notice him more and more. So what if she kept finding reasons to visit the Fire Nation just so she could spend more time noticing him. He'd noticed her, too. In fact, he'd noticed her earlier that day…just before declaring that he was going to practice more.
"I guess all that practice didn't really help, did it?" Katara asked, not bothering to hide the fact that she was watching him intently as he undressed.
"No." He dropped his pants and kicked them to the side. "It never does."
Katara ducked under the water, suddenly very much aware that she'd gone swimming naked, even more aware that Zuko might not know that. Terribly aware that she felt a strong flutter in her stomach as he stepped into the water, his face only slightly red. She tried to swim away, feeling self conscious and foolish, because looking was one thing, and just because you looked didn't mean you were interested. She could be making everything up. Maybe he really did just enjoy spending time with her. Maybe he told everyone that he missed them when they were gone and that life was boring without them. Her heart stopped when he grabbed her hand, and they surfaced together, his face redder than it was before. If he hadn't known that she was naked before, he certainly knew then; the clear waters of the pool weren't going to hide anything.
"Why'd you run—"
"I should have known you'd be a good swimmer—"
He smiled nervously, hesitantly moving closer, then opened and closed his mouth a few times, just on the verge of saying something. Trembling, Katara moved a little closer, aware of how warm the water was around him, and placed her hands on his shoulders. She shrugged, forcing herself to look him in the eyes, to not notice how heavily he was breathing, to not focus on his hands as they barely touched her hips.
"I…I got a little nervous," she said quietly. "I thought that…maybe I'd read the signals wrong. Maybe you just missed everyone."
"I do miss everyone." He pulled her closer. "I just miss you more."
He smiled at her, his usual, shy, sweet, beautiful lopsided smile, and Katara pulled herself flush against him, loving the way he inhaled sharply, twitching with indecision.
"You know," she said, leaning her head on his shoulder, "I came here because the water was nice and cool. It's already hot enough out here."
"It's not my fault, really, you—"
Katara cut him off with a kiss, afraid that she might lose her nerve, and Zuko responded immediately, meeting her with a passion that surprised her. His thumbs rubbed delightfully hot circles on her hips before sliding down, grabbing her butt firmly and pushing into her. Katara whimpered, nearly slipping under the surface. Zuko broke the kiss abruptly, grabbing her and keeping her from sinking.
"Never thought I'd see a waterbender nearly drown," he said with a smirk. "Come on. There's something I want to show you."
He swam off toward the waterfall, and Katara followed, heart racing, lips still tingling. She could still feel his hands on her, gripping tightly… She shook her head to clear it as they passed under the waterfall, and into a cave where the water was almost chilly. Barely any light made it into the cave, and they swam down a little ways, until the thundering of the waterfall faded into something much more pleasant.
"I used to hide here all the time as a kid," Zuko said, pulling himself out of the water. "My mother used to get so mad at me.
Zuko climbed out first, then turned to help her, but rather than accepting his hand, she pulled herself out slowly, watching the way his eyes travelled over her body, the blush going from his cheeks down to his shoulders. He watched the water drip from her breasts, his mouth open, before taking a deep breath and closing his eyes. When he opened them again, he had that silly little half smile that was so him, and it was stirring something deep inside of her, and it was hard to tell who moved first, but she was in his arms again, their kiss rough and passionate. He groaned as he grabbed her bottom again, pulling her even closer, and she felt him, letting out a slight gasp as she wound her fingers in his hair.
"I want you," he said, grinding into her. "Agni above, I want you."
Smiling, Katara stepped back, her whole body on fire, simply unable to get enough of the hungry look in Zuko's eyes, and she slowly sank to the ground, biting her lip as she beckoned him to follow. He laid down on top of her, his body like fire, and Katara gasped, arching into him as his tongue touched her neck, and this was sweeter than all the dreams she'd dreamed about him, because she couldn't imagine the way her skin would feel as he drug his fingers up her thigh, gripping her leg as he roll his hips into her.
"More," she begged him, her hand firm in his hair as he took her nipple into his mouth, and it was heaven.
Gasping, Katara pushed at Zuko's shorts, her body shaking with anticipation, because she wanted all of him, and she tugged at his hips until she could feel him right where she needed him. He kissed again, roughly, and slowly he entered her, and a shudder ran through her body, from the top of her head, straight down her spine and into her toes, and she moaned loudly, her voice echoing in the cave as she tilted her hips. His movements were sweet and gentle, his hands caressing rather than gripping, and really, she appreciated the care he was taking, but it just wasn't enough.
"I'm not some pampered maiden," she said breathlessly, digging her nails into his hips. "Give me more."
Cheeks red, Zuko blinked as if he was trying to clear his mind. "I don't want to hurt you."
"You can't hurt—"
Her sentence was off as he slammed into her, her moan so loud that it made her throat ache, and three times he rammed into her, rocking her whole body, and this, this was what she wanted. She grabbed his hips again as her muscles clenched around him, begging him not to slow down, not to stop, and when her breath started coming in short gulps, her back aching, she threw her leg over his hip, keeping him from going too far, and her name was a breathy whisper on the air, its echo intertwining with her moans. His arms shook as he rammed into her, steam on his breath, and laughter bubbled up inside of Katara as she raked her nails down his back. It was a weird mix of laughter and tears, and she reached out, involuntarily calling the water to her, and a small wave crashed over them, and she swore she could hear the water hissing as it hit Zuko's skin.
"Sorry," she stuttered, her entire body quivering.
Zuko only laughed, leaning down to kiss and lick and bite her neck as his pace quickened, and she screamed as he bit down on her shoulder, her orgasm coming on her suddenly, and Zuko collapsed on top of her, struggling to support his weight as he refused to relent, pounding her until her eyes rolled back in her head and her muscles spasmed uncontrollably. Katara raked her nails down his back and he thrust into her powerfully four times before the shaking passed from her into him, and he was hot inside of her and it was beautiful and delightful and a million times better than anything she'd ever dreamed. Panting, Zuko laid down next to her. Still convulsing, Katara crawled over to him. They lay, limbs entwined, waiting for their heart rates to return to normal.
"Your back," Zuko stammered, "it's not too scratched up, is it?"
Katara waved this away. "I've had worse during the war. But I'd be willing to let you try again."
"Give me about five minutes," he said, pulling her on top of him.
"What about our family? They'll come looking for us."
Body still tingling, Katara rolled her hips against Zuko, loving the way his body twitched beneath her. He shrugged, smirking as he held her and pushed into her.
"We've got the rest of this vacation to spend with them. Right now, I don't want anyone but you."
It didn't take five minutes for Zuko to be ready again, and it took even less time for Katara to forget that people might be looking for them. This night, they would spend alone.
A/N: An anon on Tumblr asked me for some zutara smut by the lake, and it took everything in me to keep this as a one shot. Hope you guys enjoyed!