Emily rolled onto her side next to John and placed a webbed hand on his shoulder.
"Honey..."
John looked to his girlfriend and his eyes went wide.
"You're a...mermaid?!"
Emily ran her hand down John's chest. "I am now, thanks to you."
She continued her hand down to his groin and stroked it with her webbed hand, quickly bringing John back to attention.
"That feels so good. Better than usual. Your hand feels different."
"So you like my new form?"
John looked his girlfriend's mermaid form from top to bottom. "Yes, it's very sexy. Sexier than I would have guessed." His continued erection agreed.
John ran his hand along Emily's fish tail. He was a little surprised that while it felt sleek it still felt warm unlike an actual fish. For Emily, the sensation was amazing. Short of actual sex, it was the best sensaation ever - better than earlier in the day when she'd massaged her newly expanded breasts with her newly webbed hands. John noticed the pleased look on Emily's face and continued to rub her tail. Emily began to practically shudder.
"Let's continue this in my whirlpool" she managed to gasp.
John scooped Emily up off the bed and carried her into the bathroom and lowered her into the whirlpool. Emily slid out of his arms to the opposite side of the whirlpool, enjoying the feel of the saltwater. She stayed submerged, breathing through her gills. John watched her beneath the water for a moment, finding her even sexier in the water than she was in bed. He climbed into the whirlpool.
Emily crossed the whirlpool and pushed John into a seated posistion with her tail between his legs. She wrapped her arms around him and pressed her lips to his. But she didn't want to wait any longer. Moments later she slid onto John. They rode the waves of pleasure in the whirlpool. The sex was better, not only because she felt better in the saltwater but - as she had learned fingering herself during her first transformation - her mermaid vagina could provide a sucking motion her human vagina did not. She was able to keep John on the brink impossibly long.
Finally she could control it no longer and began to orgasm, John joining her moments later. As they had twice before, the orgasms brought forth the salty substance from her nipples. Now was the time!
"John, suckle me! Drink from my breasts and become like me!"