Isla was in heaven, her upper half basking on a rock, warming in the sun, while her lower half was submerged in the rock pool, and her hands twisted in Belle's hair, the mermaid eating her pussy like it was her first meal in weeks. Moaning and arching against the rock, her legs over Belle's shoulders as the mermaid licked and sucked her clit, she squirmed in the water as the pleasure wound up like a spring inside her, tighter and tighter and tighter...
Belle held onto her thighs, two fingers sliding inside her as her lips latched around Isla's clit, and as she curled them inside the human, Isla cried out in delight, jerking against her face as she came. Belle continued to stroke her walls, drawing out the orgasm until Isla was a whimpering mess, trembling and tugging on her hair, and then she finally stopped. Peering out of the water, she grinned, hands trailing up Isla's body. "You taste so delicious, my human."
Isla giggled, sliding down against the sand till only her head was above water, pulling Belle on top of her, leaning in to kiss her salty lips. "You taste even more delicious, my mermaid."
Belle smiled against her lips, deepening the kiss, her long tongue sliding between Isla's lips and teasing the human's as she settled between her legs. Isla could feel Belle's slit, puffy with arousal with her cock- that's what Isla had started calling it, though it wasn't precisely that- starting to emerge put of it. Right now it just felt like another pussy, grinding against hers, and she slid her hands down Belle's tail to press her harder against her. Belle gasped, rocking back against the human, and her tentacle-like cock emerged fully and slid right inside Isla's sensitive pussy, filling her up with the cold appendage that quickly warmed up with Isla's body heat.
Isla groaned, pressing up against Belle's cold body, their breasts rubbing against each other as Belle started to thrust, the water growing choppy around them. Belle was starting to gasp for oxygen, unable to stay out of the water for very long, and Isla pulled her down into the water, for a moment forgetting that she couldn't breathe in it. It just felt so good, kissing Belle and being filled by her, and she moaned, muffled by the water, as Belle started to fuck her harder. It was lucky that she could hold her breath for as long as she could. But she had to breathe sometime, and eventually she flipped them over, gasping for air and starting to ride her hard. When they came, they came together, moaning in unison and leaning in to capture each other's lips again, hungry for each other.
When they were eventually finished, curled up together in the water and Belle examining Isla's fingers curiously as they pruned from the moisture, Isla pressed a kiss to Belle's cheek. "So. How long does this heat last? When will be the last time we can do this?"
"Usually, it only lasts a few days." It had been at least a week of meeting each other in the rock pool for wild, passionate sex, with no signs of it stopping. "But it continues if I don't make an egg."
"You can't make an egg with me, can you?"
"No." Belle smiled and turned to Isla, her expression playful. "Which means we can keep doing this forever!"
Isla laughed, nuzzling her nose. "Won't everyone wonder why you're still in heat? Don't you want an egg like everyone else?"
"If I had an egg, I wouldn't be able to do this anymore. Our heats are once a lifetime." Belle shrugged, her fingertips trailing over Isla's body. "And it won't be so noticeable. Even if they did notice, it's not unheard of to miss out during mating season. Sometimes there are odd numbers and someone doesn't get paired up. They just have to wait until next season when the next group goes into heat. Sometimes they go and find other pods. I've never heard of anyone finding a human, so I guess I'm the first!"
"Lucky me... The first to fuck a mermaid, and to get her all to myself, forever," Isla grinned, leaning in to kiss her, pulling her closer.
Lost in each other, they didn't notice a pair of eyes watching them from the deep, until Belle froze and looked around, alert and scared. She let out a sound, foreign to Isla's ears, her native language. A pause, and then an answering sound. A head rose out of the water beyond the rock pool, and Belle relaxed, shaking her head. "Oh dear... She must have followed me."