She couldn't believe her father had left that damn dog in the back yard. A poor little stray was one thing, but this beast was another entirely. He had to be the biggest mastiff she'd ever seen, a literal barrel of a chest swelling under a huge head – a long tongue handing out the side of his snout and almost touching the cement by the pool as he lazed in the shade as if he owned the place.

When her dad had left for his meeting, he'd told her to keep the back gate shut tight and not to go out in the backyard since the dog wasn't used to her yet. The dog outweighed her by at least 100 pounds. Great advice, but there were two problems: #1, she was spoiled rotten and whatever didn't go along with her plans didn't go anywhere – and #2, today the Princess was planning a whole day out by the pool getting a strong start on her summer tan. School was officially out yesterday, and nothing was getting in the way of her "first day of summer vacation ritual" – not her father, not his damn philanthropy and CERTAINLY not a damn dog.

She'd just turned 18 a month ago, and she had the body that every woman thinks every man wants (and that every woman also hates her for): huge tits, a waist that would make Scarlett O' Hara enviously green and perfectly peachy ass. She always sunbathed in the nude - the Princess abides no tan lines after all. She had the house to herself for at least the next four hours, and she was determined that no tan line would ever mar the transcendent perfection she saw as her body.

She had to put something on to wear out the backdoor and down the porch steps as she wouldn't be completely out of sight from the neighbors until she hit the lawn. She put on her favorite bikini (that her father didn't know she owned) – a blood red suit that had only strings attached to two small postage stamp sized patches that barely covered her nipples (but certainly not her areola) and a thong that held up the smallest triangle of fabric ever made, which was - in theory - meant to cover the front of her completely shaved pussy.

This suit always turned her on. She knew what she looked like in this suit. She remembered that legendary pool party she had one hot summer night last year when her father was out of town. There was no alter erected in her honour in the football team's locker room after that one.

As she looked at herself in the mirror before she went downstairs, she felt that familiar wetness moistening the insides of her thighs. It almost seemed as if a hot breath was undulating out of her pussy. She slid her fingers under the triangle for a moment, pinching her swelling clit and bending her knees to push her hips out and heighten the sensation. Her large nipples were already swelling, and she pulled a postage stamp aside to pinch her left nipple and twist it painfully between her first two fingers.

She grabbed her goody bag to take down to the pool with her. She was horny as hell, and she decided she might as well work up a sweat while she was getting that fabulous tan. Before she walked out of her bedroom, she went into her closet and found the innocuous looking bag that held all manner of dildos, vibrators and other sex toys. She was having some fun this afternoon. She was an exhibitionist at heart, and even though she knew the high fence surrounding her backyard would obscure all view of her, just the idea that she would be completely naked and masturbating wantonly out in the open sent another little electric thrill deep into her cunt.

When she walked outside, the dog seemed to be watching her as if he knew what she was thinking. DAMN. She'd forgotten about that damn dog again.

She just couldn't get over how ridiculously HUGE he was, and he didn't look as though he probably smelled too good either. She could see his dick sliding quickly into view at the sight of her, and she was surprised at her reaction to that. Instead of the revulsion she knew she should be feeling at the idea of the big hairy beast lusting after her, she could feel her instant physiological reaction – her pussy going from very damp to so damn wet that she could hear it squishing between her thighs every time she took a step.

Even the idea that he might be dirty turned her on that much more. God knows where he'd been. She immediately knew what she was going to do, and she knew it was disgusting and completely unnatural. Ironically, that's what she liked about it. She'd read stories about women that enjoyed this sort of thing before. While she always thought that sort of urge MUST be wrong, she couldn't help but always be aroused when she got to the part about the big dog literally taking the pussy attached to the slut who was down on all fours, begging for him to make her his bitch with his big fat doggy cock.

She went to the chaise lounge and in two quick motions she was out of her suit. Naked, she sat down and leaned back. She opened her goody bag and took out 3 clothespins. She clipped one onto each hard nipple, hissing in air as the sharp pain shot through her tits and down to her clit, causing it to begin throbbing. She was going to save that last clip for later. She began rubbing her sopping pussy, circling her clit in slow, lazy strokes. After a few short moments she began to smell her juices as they were now leaking out of her hole faster, and just at the moment she realized she was more pungent, so did the dog.

Immediately he was up and galloping around the side of the pool to where she lay with her legs spread wide, her fingers now sliding deep into her pussy. Just as the dog skidded to an eager stop next to her, she pulled her fingers out and he greedily licked them clean. She could see his eyes beginning to glaze over – animal instinct was a powerful thing. She pulled her fingers away from him, and he followed them in a trance straight to her spread cunt. Without missing a beat, he flung himself face first between her legs.

His long tongue seemed as though it had been made to snake deep into her pussy – as deep as she could imagine any cock going. Each stroke began with his pistoning that tongue into her, and it ended with almost an artistic – and very satisfying - swirl around her clit.

She had started off so wet already, and her clit had been so hard and distended at the thought of what she'd planned to do, that she was cumming hard in the dogs mouth very quickly. The harder she came, the deeper he licked, which set off her off again almost immediately. Just as she was beginning to get dizzy from cumming so hard and for so long so quickly, she turned her head to see that his cock was now fully erect. She'd never seen anything like it – SO BIG! It was at least 10 inches long and so thick that she nearly came again just at the though of what her pussy would feel like as it was stretched around that thick, red, slimy cock.

She leapt to her feet, and the dog immediately began growling – thinking that she was planning an escape. "Yes, you fucking nasty mutt – you're going to make me your bitch," she snarled back at him. She pulled the mat off of her nest and threw it on the cement next to the chaise.

She dropped to her knees on the softer surface, and pulled an inflated pool toy under her abdomen on which she could cradle her horny little body. She laid her arms on the lounge and spread her legs wide. She immediately felt him snuffling at her pussy, as if he was actually trying to insert his snout directly into her cunt.

Then he was on her. She was pinned beneath him as he reared up on his back legs and put his paws on the lounge on either side of her arms. She felt him humping the air furiously, desperately trying to get his huge cock into her aching cunt. She couldn't move her arms to help guide him, but she did lift her ass higher into the air – hoping that it would give him an easier target. He hit home.

He was so eager to fuck her that he jammed his cock in to his growing knot, growling lowly as she screamed in pain and pleasure at the ferocious invasion. He humped her at lightning speed, now beginning to whine and snarl, snapping at the air in his frenzy to split her open with his cock. She pushed eagerly back against him, feeling his knot brushing her clit roughly with each stroke. She wanted to feel her cum dripping down his shaft as he fucked her. She was finally able to slide one arm underneath her body and she remembered that last clothespin. It was lying on the cement just under the chaise and luckily in a direction that was within her reach.

She grabbed it and could feel the orgasm building at the very idea of what was about to happen. She opened the clip, reached down, positioned it over her clit and leg go. A terrific pain shot through her cunt, and immediately the orgasm began. She screamed and convulsed as she felt the waves wash over her.

She began ejaculating around his huge cock, and she came for so long that she began to be afraid that she might lose consciousness – it just wouldn't stop - partly because the knot that had earlier been stroking her clit was now making it's way slowly into her. The dog's strokes were building in intensity, and she could sense his desperation to fully fuck his knot into her.

She again began pushing back hard into him, and after a few moments she started giving the clothespin on her clit a quick little twist or tug with every few strokes of the giant cock working it's way through her. The knot was about halfway in and she couldn't take it anymore. She grabbed the clothespin and twisted it fiercely, causing another mind numbing orgasm to grip her body. As her pussy gripped convulsively on his cock it seemed to set off the dog, and instead of being pushed out of her hole, he became even more excited. With a loud yelp, he shoved with all his might and his knot became lodged in her ravaged pussy.

She moaned like the whore she was, and ground herself into him. She was now lost in a daze of abusive, painful and completely satisfying sex. She did not hear the car pull up in the driveway as the dog worked himself up into a frenzy, and shot his hot cum through her cervix, setting off what she thought was her last orgasm. She did not hear the car door slam... or the back gate open. What she did hear were the shoes crunching on the gravel as they stopped just a few steps away from her.

She realized that her attitudes about this dog staying around a bit longer were changing dramatically as she opened her eyes and looked up. Even then, she was still lost in the daze of being so thoroughly fucked - and subsequently so exhausted and completely satisfied - that she couldn't even feign horror, embarrassment or chagrin at the sight of her father standing there with his hardening cock thickening in his hand.

"Hi Honey," he said. "Daddy's home early. Can I be next?"