Caroline and Topaz kissed with furious lust. Caroline hadn't had sex since before her divorce.
Topaz had been trapped in the mansion for far too long for a mermaid. She had made advances on Neil who seemed at first to have rescued her mostly out of lust, but then seemed to have second thoughts - perhaps conflicted about his existing emotions for Caroline and his newfound emtions for her? But now she had a willing partner and it would ensure Neil would return her to the sea.
Topaz began to work her way down Caroline's body: kissing down her neck then her tongue working over Caroline's breasts then down her stomach, at last reaching her destinantion. Caroline was wet and willing. Topaz tongue entered and Caroline began to moan with delight, her eyes rolling and her body practically twitching in ecstacy as Topaz worked her magic. In a way that's what it was: while regular sex was the prefered way to transform a human into a mermaid, oral could work as well.
As Topaz did the work with her tongue, the changes began. Orange scales began to appear on Caroline's legs. Her legs, originally spread wide began to slowly draw together. Topaz had to pause her work and lift herself up so Caroline's legs could pull together. Her legs were now covered in orange scaly splotches and would not seperate, but they were clearly still legs.
Topaz remounted Caroline and their mouths and tongues met again for a moment. Caroline agained enjoyed the sensation of Topaz's tail sliding over her body.
"My legs feel funny" observed Caroline.
"Your change is half complete. I have begun it, but only you can finish it. Are you ready?"
"Yes."
Topaz pulled herself forward, bringing her sex to Caroline's mouth. Caroline used her hands to pull it to her mouth and explored another woman for the first time with her tongue. Topaz moaned a little. "Tastes fishy" Caroline observed before trying to return the favor of Topaz's actions from a few minutes earlier. Topaz shuddered with delight as Caroline worked clumsily but energeticaly. Caroline could feel her legs merging and her feet flattening. As Topaz neared climax, she slid back down to resume an equal posistioning attop Caroline. Both females were breathing heavily as the sensation of Topaz's tail drove Caroline wild. But now as Topaz's tail slid not against Caroline's legs, but against her newly formed tail it felt even better.
Tails rubbed together, lips and tongues met, hands roamed about. Finally both bodies shuddered and exploded, reaching orgasm together.
They collapsed and Topaz rolled off Caroline who was now completely a mermaid, with a bright orange tail. The two mermaids' tails entwined as they lay on the wet pool deck.