"I don't think there's anything you can tell me that is weirder than what's already happened tonight. I think everything that's happened is going to stay between the people here. We'd never live it down. So yeah, I promise not to tell anyone your secret."
Crystal uncurled slightly and looked down at the pool, and Kyle thought he could see longing in her expression.
"I suppose you're right about that..." She drummed her fingers on her legs nervously, "The truth is...my mother, one of my mothers, wasn't human... She's was Child of the Sea...umm...a mermaid, to most people. She fell for my other mom, the one everyone in school has met, on vacation to the coast, one from land and one from sea. The next two weeks were apparently an amazing whirlwind of love and...ahem, passion." Crystal blushed a little as a moan punctuated her choice of words. "Anyway, on the last day, when my human mom had to leave, my mermum asked her if she had kids and to which she replied she couldn't. Mermum offered to perform a ritual that would allow her to have a half-mermaid baby as thanks and to remember the amazing fortnight by, as she couldn't stay away from the sea for too long and needed to return home."
Crystal paused when she saw a small look of confusion Kyle's face, "Sorry," he said, "Single pronoun, I think I followed it though. No questions about a dad?"
"No...I was apparently the result of a one night stand during the vacation."
"So can you like grow a fin and breath underwater and stuff?"
"Sorta, I mean I can breath underwater and supposedly survive intense pressure changes that would liquefy human organs. My ears don't even pop on airplanes. I don't get a full tail fin, though. My hands and feet get webbed and I grow some thin dorsal fins down my spine when under for a while."
"No scales?"
"Oh sure, I get scales, but only after about an hour and only on my thighs." She noticed Kyle look away, cheeks red, "I hope I look good in your imagination." She chuckled as his nose started to redden. "I-Thanks for listening to me Kyle." She rose slowly to her feet and stepped to the edge of the pool. "Those four are going to be a while and will probably fall asleep when they're done, so I'm going for a swim. A long swim. Without a swimsuit. I think they might miss you up there, but you're free to watch and I wouldn't say no to a swimming partner."
Before he had even full absorbed what she said, Crystal was already stripping herself down.