"WHAT?!?" Your eloquently answered to the mermaid's incomprehensible blabbing.
That prompted the fishy-girl to add… Something you will never know, since when she was about to speak again, another mermaid literally jumped at you.
Your arms were full of the newcomer, who firmly attached herself to you, her arms around your neck. She redressed herself before kissed you!
… On your forehead.
Then, she said "Don't mind Ambrosia, she's the mermad of our cove."
Puzzled, you asked "Aren't you a mermaid to?"
"Hm? Oh! I didn't said merMAID, but merMAD! It's like a madman, or madwoman in her case, I suppose, but being a merfolk instead of human. She's nice, but 'not whole in her head' if you catch my drift." Said the one still occupying your arms, promptly adding "But don't worry, she isn't dangerous! Not at all!"
Raising an eyebrow and with a slight smirk, you retorted "And jumping in my arms, out of the blue, to kiss me on the forehead isn't madness? Not that I'm complaining, your quite a lovely sight to be holding."
Blushing because of your cheesy words, she was about to respond when Ambrosia said "If you give her your queen of hearts, she will let you touch her ace of spades." The mermad then looked at the one that kissed your forehead, adding "I'm a mermaid, not a merwoman. I don't know what merwomen are, but I'm not one, I'm a mermaid." before returning in the water, with the other merfolks.
After that, the kissing one finally got off of you. Siting on a nearby stone, she silently ask you to sit next to her. As soon as you comply, she declared "It was a magic kiss."
"A magic kiss?" You ask, in the hope to have more details.
"That cove is magically cloaked. The fact you were able to find it prove you wouldn't do anything that could put us in danger, not willingly. The first reason was to cast a cloaking spell on you, preventing anyone to find this cove by following you, in case you ever decide to come back." She explained. "I'm Adjutant Ondine Louise Neptune, of the merfolks Gendarmerie and the head of this cove's security. But you can call me 'Di', all my friends do."
"Wow…" Her introduction let you speechless. After some time, you finally found your voice and presented yourself. "My name happen to be Louis Nicolas Dubois. I'm an ordinary and average human called 'Lou' by most of his friends." Before asking "Adjutant NEPTUNE you said? Any connexion with the Roman god of seas?"
"No… No, I don't think so. You earth-dwellers got a god named like me? Wow… It's just… Wow…" It was Ondine's turn to be speechless.
"Well, It's first was known as Poseidon, the Greek god of the seas. But yes, Romans called him Neptune." You confirmed. "So… You said secrecy was the first reason for your magical kiss. What is the other reason?"
"Two other reasons, in fact." The gendarme corrected. "Not all merfolks speak English, some don't even speak any human language at all. So I made you able to understand our magical language, you should even be able to speak in it."
"Wow, that's a heck of a welcome gift… Thanks! And what about the third reason?"
Ondine blushed. "I… " Instinctively, she took your hand like a girlfriend would have, making you blush too. "I'm not an ordinary mermaid. I'm something of a rarity, something that just born commonly enough to be known of. I'm what is called a siren. The only beings immunes to my hypnotic voice are merfolks, any mammals having echolocation and, since this very night, an earth-man known as Lou."
In the background, two mermaids are gossiping. "Poor little earth-dweller, It look like he become the new shew-tow of our ace of spades." One said. The other added "Bah, you know how humans are. His biggest wish is probably to become her sex-slave!"
That last phrase was Ambrosia's cue to hit the two gossipers on the back of their head, admonishing them wile still being her usual self. "He's nice, he's my friend! So you shouldn't badmouth a queen of hearts."
But you weren't aware of the two gossiper or your mermad protector, Adjutant Neptune and you being far to entranced by each others body.
Usually, girls like Ondine weren't your type. (Her fish-tail notwithstanding.) But since the moment she jumped in your arms, everything in her seemed absolutely perfect to you. Be it that tomboyish haircut, which strangely looked so girly when associated with her angelic face. That small chest at the top of her hourglass figure, all that hidden by her neoprene uniform. Her arms, that looked strong without being less feminine. Or even the shark-like skin of her tail, who started as black as her hairs on it's base, then turning the same marine-blue as her eyes toward it's end, a more classical caudal fin of the same blue topping it.
Looking at each others, eyes in eyes, you approached your face from hers, about to kiss her on the lisp. But before you do, she gently pushed you back, her finger on your mouth, saying "Sorry, but you shouldn't kiss merfolks on the lisps."
Stuck by incomprehension, you simply ask her "Why?!?"