Tammi wasn't the smartest of girls. It wasn't fair, really; she hadn't been blessed with smarts, but she hadn't been blessed with looks either. She wasn't ugly - she was plain. Her large eyes were slightly too far apart, dark brown, lips a little too large. She was short, too - only five foot three, and a little bit on the chubby side. The only thing she was proud of was her hair. Naturally dark brown with a hint of red, it grew almost to her waist in a shimmering curtain. Every day Tammi would carefully brush it, when she woke up, often twisting it into an elaborate style, then carefully brushed and plaited before she slept.
The only thing Tammi considered herself good at was swimming. It was more of a pleasure than a skill. She never placed in competitions, and couldn't afford to go often enough to make it anything special - so now, twenty five and heading home from work, she was proud that she had gone swimming every day this week. An independent adult, working hard, doing the things she liked. But tonight she was leaving out the swimming at the pool; it was a beautiful, shimmering summers day, and she was looking forward to getting a delivery.
The lorry was at her house as she approached so she ran the last dozen paces and caught up with the man with the large box. "Hey." she panted slightly and the bloke looked back grumpily. "This yours?" he asked and she nodded, signing the electronic pad and taking it gleefully. Running up to the steps, she let herself into her small but thankfully cool maisonette flat. Placing the box onto the table she didn't even bother getting changed before she carefully cut it open, pulling out the folds of shiny, shimmering material with a joyful look in her eyes. For a moment, she almost managed to look pretty.
It was a swimming aid she'd wanted since she was just a girl. In a dark blue edging into purple, it was an imitation mermaid tail with a dual-fin in the tip, so she could slide her feet into it and swim like a real mermaid. Spreading it delicately out over her sofa, she inspected it, with it's faint scale pattern and stunning colour - it was absolutely perfect. She could've skipped as she got changed into her casual clothes, folded it and packed it gently into her swim bag with a towel, and went to grab the bus down to the lakeside.
It was a short walk but a nice day, so she headed comfortably in the evening light toward the recently cleaned up lake. Tammi hoped that, by now, the children and others would've gone and she could practice in the waters alone. It seemed that wish was to be fulfilled; as she approached the bank, there was no sign of any people around, and still plenty of light to swim by. Excited, she opened her bag, and, checking around quickly, slipped off her shirt and trousers. Already in her bikini swimming bra, she stripped off her lower half, folding it neatly, then took the fabric of the tail in her hands. Carefully, gently, she lifted her legs and slid them into the fabric, flopping ungracefully onto her front to slide it the last few inches and slot her feet into the fin at the base.
Tammi took a moment to appreciate the way it formed a seal at the top around her stomach, staring at the strange appearance of her body, running a finger up her legs. It added a good foot onto her with tail - and she thought she looked amazing. Try to avoid the mud, she slid herself over the grass and dipped the tail into the water. The tips of the fins, specifically designed, moved a little in the water and she let out a soft noise of happiness. With a firm push, she slid almost to the top of the tail, feeling only a little warmth through it. The water was pleasant. Her grin felt like it was splitting her face as she pushed her upper body in, keeping a tight grip on the long grass at the edge of the water.
It was deep, a man-made lake, but clean to swim in. She gave a flick of her legs and delighted in the power it gave her. Taking a breath, Tammi turned and went under the water, kicking and rocketing along. It felt amazingly natural to slide through the water like this, and she found herself surfacing to breathe and diving as if she had been doing it her whole life. Deciding to take a breather, she surfaced and gripped the side again, looking out through some dripping hair at the low sun, closing her eyes and enjoying the warmth and the slight probing at her entrance...
Wait, what? Tammi snapped her eyes open and kicked her feet with the shock. It felt like something warm and slick was pressing against her crotch, but there was nothing outside her. Then she realised that it was pressing from inside. But that was impossible. The tail was skin-tight and nothing had been in there before she put her feet in. There came another push, firmer, more sure this time - almost with more shape. It didn't feel like anything she'd felt before... another push, this time gaining a little, actually pushing her lips apart and diving into her. Tammi let out a soft gasp, kicking to try to get away from it, ending up half on the shore with her front down and rear up.
Was she being molested by a ghost?! No, that was stupid. But this time something pushed, hard, penetrated her, sliding in. Nothing like a cock at all. Almost hot, thick, it filled her and pushed in then slid out again and she felt herself give out a low, hot moan as juices began to run. It felt good. It'd been a long, long time since she'd had sex, years, and this felt good. Maybe I'm hallucinating, she thought, letting herself slip back a little into the water; Maybe I've drowned. Then there came another thrust and instead of fading it began to take up a beat. She tangled her hands into the grass, breathing hard as whatever it was began to fuck her. Her body trembled and her legs kicked, but she couldn't spread them or get away. Whatever it was was inside the tail.
She was rocking her hips now as it thundered in and out of her, seeming to swell and changed shape with every thrust, filling her, hot and heavy inside her tunnel, and then it froze and seemed to pulse once. She let out a cry of pleasure as she came and felt a hot gush inside her, that didn't fade or drip out. Tammi lay there, trembling, face in the grass for what felt like hours. Instead it was about three minutes that whatever it was gushed inside her, coating her, making her tremble and tingle until she finally regained control of herself. Crawling out of the water, she caught her breath until realising it was almost dark. She didn't know how but found herself at home and crawling into bed, the tail wrapped up and dry from the sun in her bag.
The next day was her day off. After hot dreams she awoke, rolling over to blink at the clock, expecting her normal 9am; instead, it read 3pm. Sitting bolt upright she glanced out the window, astonished. She'd been asleep for eighteen hours?! That wasn't like her. Not at all. But getting to her feet she knew it was true, her legs trembling, unused to it. She spent a few hours dithering around, eating and cleaning, utterly astonished, but around six she realised there was only one thing on her mind, and she grabbed her bag from the side.
The lake was deserted and she shimmered into her tail, diving into the water. Like a hot friend from the deep, the presence slipped, already throbbing, into her slick hole, ready and waiting. She moaned; and this time it pushed her hard, no gentleness, until she was moaning loud and lewdly, not caring until it came into her, releasing just after she did. She lay there on the side until it had finished throbbing. But this time she didn't go home. Tammi let herself float on the water, staring up at the skies but not seeing. Her hands ran over the tail; she had released but still felt so hot, trembling. She had to go again; she pushed, trying to rub herself in the right way, but couldn't get a hand into the thin rubber or get enough sensation rubbing from the front.
Then it returned. Gentle again, prodding softly; feeling slightly different. There was a question here, a point of no return, but she didn't care. She needed it, deep inside her, panting as she thrust her hips against the slick mud wall. The push came, into her, deep, deep as to almost cause her pain - but not quite. She trembled as it slid out, pulsing, pushing, swelling and throbbing to test the limits she would stretch to. Then it went still again, but she hadn't gone. She gave a frustrated cry as it throbbed and trembled but didn't push. Then there was something else. A round object pressing against her, inside the tube that was in her. Something just larger than a golf ball. Then it began to slide inside her and she went, crying out into the now-chilling air.
It didn't stop. It reached her womb and there was a jab of pain, a jab that was almost pleasure, and then she felt something settle. Another was at her entrance, sliding in, and she groaned; it didn't wait to go in, about halfway through another came in, until she felt them one after the other. She went a third time, body spasming, but they wouldn't stop. Resting a hand on her stomach, face on the grass and tail twitching languidly, she began to feel the bulging of smooth, wet eggs inside her womb. Tammi laid there for twenty minutes before it stopped, her stomach that of a five month pregnant woman, except the spheres could be seen where they pressed on her skin.
She ran a hand over her stomach and trembled. The tube had gone from inside her and she felt a strange, warm pain in her legs, before she realised they weren't separate. One powerful muscle twitched below her, and she felt her slit move, realigning itself on her front. She dived and breathed through new gills - though her lungs were still there. Her eyes could peer through the water with no pain. Then another thought filled her still pleasure-drowsy mind... she was full of eggs, but they were unfertile. She needed a man. And so the new mermaid settled to the bottom of the lake, to wait... now happy with herself at last.