That afternoon, John stood staring at Amy's pool wearing only his swim trunks. "I can't believe you agreed to this" he said.
"I thought most guys fantasized about having a threesome with two girls?" Amy asked coyly as she walked by with a beach towel wrapped round her.
"Lana is attractive" admitted John "but we basically just met her this morning. And depending on what you're in the mood for I don't know what I'm actually in for."
Amy walked over and turned on the jets for the jacuzzi. "I like surprises." She walked past John, slowly letting her towel fall away, teasing him with a rear view of her naked body. Then she climbed into the jacuzzi. The roiling water made it impossible to see what was happening beneath the surface.
John took off his swim trunks and climbed into the jacuzzi opposite Amy. Only her head with her long red hair was above the water, her face bearing a mischievous smile. John felt his legs begin to draw together. He ran his hands down the fish scales of his tail. At least transformation was fun. He looked down at his chest, but it seemed normal. He felt his crotch and found his erect penis. He'd transformed into a merman instead of a mermaid. But what kind of mermaid had Amy transformed into?
Before he could find out, Lana arrived. "I hope you two didn't start without me" she said. "I've been horny ever since seeing you two this morning.
"Just getting our tails on for you" said Amy. "Come on in."
Lana approached, swinging her hips and her long blonde hair. As her skirt flew around John realized Lana was still without the panties that had brought her into the locker room that morning. She took off her blouse to reveal she didn't wear a bra either. John immediately felt himself become more aroused at the sight of Lana's amazing natural tits. Amy had nice B-cups, but Lana's were a pair of incredibly firm D's. Then Lana cast the skirt aside, giving John and Amy a chance to look over her nude body before she stepped into the jacuzzi.