Please note that this story occurs in a mythical world that is free of sexually transmitted infections and unwanted pregnancy - if you live on planet Earth please always use protection.
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A young mermaid is nineteen and ready to explore sex.
"Yawn..."
Adriel woke up to the watery world around her, her big, blue eyes taking in the sights of her room at her father's palace. As the fog of sleep cleared, she remembered that today was her 19th birthday...a thought that brought both a feeling of happiness and remorse. The happiness came when she caught a glimpse of herself in the mirror, noticing how her once-B cup-sized breasts had ballooned into a full D-cup. Other than that, she hadn't changed much in the last year or so; she was still fortunate enough to have a very small waist, flowing red hair, and a big, youthful smile that could melt hearts (and tighten pants) on command.
The remorse came when she realized that even though today was a special day, it was still a day like all the rest: a day of repetition, of water, and ultimately of not fitting in. Adriel had had a very brief crush on a human a couple of years previously, an incident that had caused a great deal of turmoil between her and her protective father. Ironically, the turmoil had been for naught, since even though the human was a kind and attractive male, he was only interested in other males. However, after having a taste of spying on the human world, Adriel found that she could not stop. Every chance she got she would rise to the surface and watch the people that resided there: townsfolk, sailors, fishermen...anyone who would come within sight of the shoreline.
Then one day, when she had just turned 18, Adriel happened upon a secluded beach area that she had never explored before. As she approached it, she saw two humans lying closely together, doing something that completely mystified her. Both of them had removed their clothes, and for the first time in her life Adriel saw genitals. The humans took turns licking and sucking each other's parts, and then the male placed his part inside of the girls and rocked back and forth until both groaned out loud and then looked exhausted (but blissful). Although she did not understand what was going on, the sight before her stirred something deep within Adriel. She had an overwhelming urge to somehow be part of the mysterious act in front of her, but her fear of humans ultimately dissuaded her. Adriel noticed that the girl's breasts looked very similar to hers under her seashells (although Adriel's were larger and incredibly perky thanks to the relative absence of effects of gravity under water), and wondered if other similarities might exist between them as well.
After a long, private conversation with one of her sister's, Adriel finally learned about the underwater version of the birds and the bees: apparently merfolk ultimately reproduced by an advanced version of binary fission (i.e. self cloning, of sorts), with no sexual component to it at all. Couples would kiss and stimulate one another's nipples, but that was pretty much the extent of things. Needless to say, that was not the answer Adriel was looking for. So for the next year leading up to this day, her birthday, Adriel would swim back to that secluded spot with the hope of catching those humans again (or any humans really); oftentimes climbing onto the shore, closing her eyes, and daydreaming about being part of their bond.
"And now I'm going to have to go to another unbearable party," Adriel said to herself.
While she loved her family very much, she hated going to social functions with them. Within the first ten minutes someone would bring up that she needed to find a husband and then the rest of the group would jump on the bandwagon. Of course she had no shortage of suitors, but a merman really wasn't what Adriel was looking for. A lifetime of kissing and nipple stimulation just wouldn't be enough for her.
"Well, it is my birthday, so I might as well make the best of it," Adriel thought. And with that she took off for her special place, wishing with all her heart that she might find that delectable sight again.
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Dustin was, by his nature, a bit of a loner. In addition to being an apprentice wizard (which lent itself to long hours in the library and general suspicion from laypeople), he simply liked spending his extra time wandering about in nature. While he frequented forests, mountains, and valleys to find components for his magical spells, his favourite place to visit was the waterside. As all sorcerers were made to do, he had picked a focus to his magical specialty which happened to be water magic. Therefore he felt a particular affinity to aquatic areas in general.
That day he had decided to explore a new beach area that was quite out of the way - partially because he was hoping to find some rare or exotic flora or fauna, and partially because he just didn't want to bump into anyone to be disturbed. As he made is way through a dense patch of brush near the water's edge, an unbelievable sight met his eyes: sprawled on the ground not 10 feet away from him was a drop-dead gorgeous mermaid lying on the sand, eyes close, moving back and forth, massaging her massive, luscious tits.
Being a man, and being a man who had fantasized on numerous occasions about sex with a mermaid (although he never quite addressed where his penis would actually go), Dustin quickly sported a massive erection. The creature in front of him seemed to be completely lost in her own world, yet he was afraid to move back into the brush in case he alerted her and she ran. Being incredibly intelligent (given his profession), he figured that she would probably run as soon as she saw him anyways. He also figured he would probably never have this opportunity again...so he pulled out his 6-inch cock and starting tugging on it at a moderate pace. Watching her beautiful face, perky tits, and tight body (combined with the pleasure from his hand), Dusting accidentally let out a small moan.
Adriel was snapped from her reverie in an instant. In a split second she had grabbed her seashells and was half-way into the water when something inside of her said "stop". Turning her head slowly, she processed the sight before her: human, attractive, tool between his legs. After a moment's consideration and telling her survival instinct to shut the hell up, she turned fully around, put her seashells back on and said, "Hello."
Stammering, Dustin replied, "H-h-hello."
"Could you tell me what that thing in your hand is called?" Adriel asked.
Blushing a thousand shades of red, Dusting replaced his cock in an instant and said, "Pardon?"
"That thing you just put back in your pants...what's it called?" she repeated.
"I'm sorry, what?" Dustin asked again. "Ummm, I mean, ummm, are you a real mermaid?"
"Of course," Adriel giggled sweetly, causing Dustin's cock to jump. "There, that thing that just twitched in your pants!"
Blushing again, Dustin said, "Ummm, it's my penis."
"Oh, a penis," Adriel replied, making a mental note. "Good to know."
"What's your name?" Dustin asked. "I'm Dustin."
"Oh, that's a nice name. I'm Adriel. Hey, there, it twitched again!"
"Oh sorry," Dustin said. "It's just that Adriel is ummm, a really nice name. Really suits you."
"Well thanks," Adriel replied. "Dustin, are you planning to hurt me?"
"No, of course not!" Dustin exclaimed. "Why would I do that?"
"Well, my people have always feared humans because we're afraid you'll try to hurt us."
"Well, I mean some people might try," Dustin began, "but only the sort who would likely hurt other humans, too. Lots of us humans are fascinated by the idea merfolk...although many of us think you're fictional creatures. Ummm, one question: as glad as I am that you're here, why ARE you here if you're so scared of us?"
"Ummm," Adriel faltered, embarrassed at the true answer. "Well, I guess I'm a mermaid who's fascinated by humans. I watch you guys whenever I have the chance. Living under the water all the time just gets so...boring. I mean, we don't even have sex!"
Dustin's mouth dropped open and Adriel's face turned the colour of her hair. She had gotten so wrapped up in getting to talk to a human that her guard was let down completely.
"Oh, jeez, I should really just go," Adriel began, turning to head back into the sea.
"No don't!" Dustin exclaimed, surprising both of them. "It's just that, it's really nice talking with you, and I'm afraid that if you go I'll never get to meet another mermaid...especially not one like you."
"What would the difference be if it was me or someone else?"