A/n: This is just a little PWP that came about after mucking about in the CS Tiny Chat last night. My mental-Killian-muse wouldn't rest until it was written. As a note, this is set AU in the Enchanted Forest where Emma didn't leave Hook on the beanstalk.
Emma dove under the water, coming back up after a few seconds. Her hair clung to her cheeks and she wiped her hands over her cheeks, pushing the hair behind her shoulders. She was well aware that she was not alone. It was actually quite amusing to know that Killian was watching her, and here she had been thinking his 'you're like breath to a dying man', was purely dramatics out of him.
"Killian, come out from where ever you are." She called, glancing over her shoulder at the shore line. There were plenty of large rocks from the cliff face where he could be hiding. "Seriously, come out or I'm going to have to come out of the lake and kick your ass."
"It depends on what the ass kicking entails?" Killian appeared from behind the rocks, a wide grin on his lips. "But by all means, come out of the water love."
"Or you could come and join me." Emma countered with a seductive smirk. "I have a spot I can't quite reach."
Killian's eyes widened as he watched the hand she had had on her cheek, slide down her neck, her chest, and vanish beneath the water, only for her to make a show of moaning. "Are you trying to kill a man at this hour?"
"Always," Emma winked at him, grinning as he started to hastily rid himself of his leather trousers and the black cotton shirt he wore. In the last few months she had realized that going against her gut instinct to leave him at the top of the beanstalk, wasn't that bad after all.
"Stop giving me the impatient look, Swan." Killian finally got his trousers down, wasting very little time before he was in the water beside her.
"You're not wet enough." Emma laughed, splashing him with water.
Killian gazed at her with hooded eyes, "Oh, but I bet you're wet enough." He trailed his hook along the curve of her hip as he stepped around behind her.
"I might be," She turned around, cocking her head to the side. "But you're not." Emma rested her hands on his shoulders and in a matter of seconds she wrapped her legs around the back of his knees and sent him falling backwards, taking her with him.
There was splashing and limbs everywhere as they tumbled into the water and fought each other to get back to the surface, laughing and sputtering as they did.
"What was that for?" Killian grumbled, shaking his soaking wet hair out.
"You getting wet." Her brows rose in amusement as she met his blue eyes, "Did you not expect to get wet coming out in the water?"
"Not exactly," He pouted, leaning in to kiss her. "But I'm not exactly against this sort of horseplay. Killian wrapped his arm around her waist, pulling her flush to him and laughing at the way the water sloshed against their skin. "Good morning Miss Swan." He gave her a cocky little half-grin as he ran his hand behind her to cup her ass.
"Good morning Captain." Emma gave a soft gasp as he lifted her up and she wrapped her legs around him. The water lapped against her breasts as the emerged partially from the water at her new height, making her kiss his lips to avoid moaning out his name.
"Gods, you're not allowed to leave the Enchanted Forest. Ever." Killian used the weightless effects of the water to help reposition her before, driving up into her. He buried his face in the curve of her neck, lazily running his tongue against the pulse point there.
Emma pressed her hands against his shoulders, using the leverage to rock her hips downwards. "This is a first for me." Emma whispered as she scraped her teeth against his shoulder. "Sex in the lake."
"We may need to make a habit out of this." Killian flashed her a grin before tilting his head and catching her lips. The angle made it difficult for Killian to let go of her hip and tangling his fingers in her wet hair like he longed to, but he was perfectly content to finish this out without caving and hauling her onto the shore.
"Killian." Emma bit down on his bottom lip as she slipped her hand between them, teasing the bud of nerves just above where they were joined. She let out a strangled cry as she felt herself starting to tighten around him, making her movements jerky.
"Emma," He groaned, pressing his face between her breasts as she arched back. If she wasn't careful she was going to make him lose his grip on her. And that was just going to a fate worse than death with his impending release creeping up on him. "Hold still." He growled against her wet skin, nipping at the curve of her breast to drive his point home.
Killian grinned as her walls tightened around him deliciously, pushing him over the edge into oblivion. He stilled his movements, his grip on her hip tightening as he steadied her.
"You're definitely coming to the lake with me more often." Emma smirked as she let her feet drop back down against the sandy lakebed, leaning against his chest as her footing started to falter. "We should get back to camp."
"Before they find out that we're quick fucks?" Killian pressed his lips together and looked down at her. He smiled sadly, brushing her wet hair off of her shoulders.
"Are we going to tell him them?" Emma looked up at him, a pang of guilt striking her as she met the sadness in his eyes.
"Of course not," He shook his head, droplets of water falling down his cheeks. "I think your mother would tie me to a tree and use me for target practice." Killian chuckled, leaning in to kiss her once more before heading back to the shore to collect his clothes. It was worth the secrecy just to have her once a week.