In the shelter of their cave, Isla let the much larger mermaid, who she had decided to name Sharky for lack of a better option, push her under the water and kiss her ferociously. Isla kissed her back, moaning as the mermaid's sharp claws trailed down her body, the danger making her core heat up and goosebumps rise under her touch. Needing to breathe, she pushed Sharky off her and rolled on top, leaning in to kiss her again as her hands wandered.
Sharky's breasts were nice handfuls, smaller than Belle, her whole body lean and streamlined. She grinned as she felt the mermaid shudder under her as she rolled her nipples between her fingers, pulling back to see the look in her eyes. Sharky eyed her as if she wanted to devour her.
"Are you in heat?" Isla hummed, tugging playfully at her nipples and shuddering at the growl she heard. Her hands trailed down to find the mermaid's slit, tracing gentle fingertips along lips that were growing puffy and slick, gazing into her eyes and watching Sharky's jaw drop as she slipped a finger inside her. "Well, you are now..."
"I mate with others... not like me..." Sharky gasped, rocking underneath Isla, pressing up against her hand greedily. Her nails dug into the human's thighs, and she passed her tongue over her sharp teeth, panting in pleasure as Isla slowly pressed her finger in and out. "When no eggs are made... the heat will come again."
"I see. You're just like Belle. You love mating so much that you have to fuck different species to keep doing it." Isla grinned, adding another finger and thrusting inside Sharky slow and deep. The mermaid made a high pitched noise, writhing under her and gasping for breath under the water, her long, dark hair spreading out under her in wild tendrils. Isla continued fingering her until the mermaid's cock unsheathed, long and pliant as it wrapped around her wrist, and Isla could feel ridges around the sides, an exciting sensation even against her skin.
Belle was watching nearby, curled in the water, sharp eyes watching them intently as she pressed her fingers inside herself. At the sight of Sharky's cock, her eyes widened, and she grinned, wiggling closer. "It's big! I want to try after you!"
Isla laughed, giving Belle a fond look, and leaned back on top of Sharky, slowly guiding her cock inside. She tipped her head back with a groan as she felt the thick appendage spread her apart, the ridges rubbing against her slick walls deliciously. Under her, the mermaid arched her back, nails digging into her thighs as she pulled Isla down against her tail and thrusted up, filling her completely. "Fuck!" Isla gasped, her head spinning as Sharky started to fuck her from below, rough and wild as the water splashed around them.
Belle watched open-mouthed at the scene, her own moans joining the others as she pleasured herself to the sight of Isla and Sharky fucking hard. Her eyes fixed on Isla, the human bouncing on top of the other mermaid with lidded eyes and parted lips, flushed and moaning. Her breasts jiggled in her red bikini, until one of them was dislodged by the rough movements and fell from the flimsy fabric, soft and round with rock hard nipples. Noticing the way Belle watched her, Isla grinned and removed the bikini, tossing it to the mermaid, and cupping her breasts with a groan, playing with her nipples as Sharky fucked her hard.
It didn't take long before Sharky's thrusts grew erratic and more desperate, and her hands clutched at Isla's skin, hard enough to make her bleed in some places, although the human couldn't feel it as the pleasure grew inside her. Isla moaned in delight, grabbing onto Sharky's arms, and for a moment they found each other's hands, entwining their fingers sweetly, before the mermaid tugged her down and rolled over, pinning Isla into the sand. Isla could only moan helplessly under the water as Sharky curled her tail around her and tucked her face into the human's neck, sinking her teeth into the tender skin. She should have felt fear and pain, but the mermaid thrusted hard into her, pressing all the right spots again and again, until Isla was seeing stars, crying out under the water. Sharky wasn't far behind, jerking as she came, filling the human with sticky mermaid seed. It felt incredible and Isla pressed her legs against Sharky's sides as the mermaid slowed her thrusts, rocking her hips against her and milking every last drop from the long, thick cock.