Jen ran behind the school to where she knew her friends were keeping a stray dog. He was a large, golden tan colored German shepherd mix that the other kids called Max. When she found Max wandering around looking for food, Jen whistled for him to coax him over, she couldn’t stop imagining what it would be like to have a belly full of his puppies soon and was giddy at the thought. “Max! Here boy!” Jen called to him as he plodded over to her. She dropped her skirt and presented herself to the stray on her hands and knees. Max took a deep sniff and licked her snatch a few times, his red rocket visible from his sheath. Jen began to have regrets as she saw the size of his member and prepared herself as he crashed into her back. She felt his claws dig into her thighs as his fore paws pulled her supple body closer. Jen felt his hot breath as he panted in her ear, poking and searching for his target below. When he finally hit home, Jen howled and Max gently bit down on her collar as he started going to town. His searing hot poker began thrusting quickly in and out of Jen as her tight walls clenched around it, completely stretched to their limit. Jen began rocking her hips in time with the large canine, feeling his soft furry underside tickling her back and rear as he thrusted into her. His pace quickened, and Jen knew the knot would be coming soon as she felt the base of his doggy dick thickening. She slammed her hips back against him and his large knot slid in to her passage. Jen and Max were now one as they howled together, rutting frantically and racing each other to the edge. Max pulled her in as tightly as he could with his fore paws, his bite on her collar tightening a bit as well as his thrusts became quick and shallow. His furry balls slapped against Jen’s ass as he neared the finish line. Jen moaned loudly, cumming around his cock and coiling tight as he began to release his seed deep into her womb. She felt the hot liquid filling her up as he dumped his balls inside her, pump after pump of molten cum. The girl screamed in ecstasy as she took every drop of his seed to ensure her pregnancy, and Max’s knot plugged her hole to further guarantee his success. She could feel the dog on her back ease up a bit as he hopped off, still knotted to the young girl. He stood ass to ass with Jen for a while, panting hard. Jen remembered that she heard somewhere that dog knots can stay inflated like this for around a half hour, maybe even longer. She began to feel a tickling sensation as she reached down to feel her very full belly. Two rows of dark teats were starting to form on her underside, with a total of ten sensitive canine nipples spanning the length of her abdomen. Jen knew this meant in one hour she would be due to give birth to Max’s litter of puppies. She reveled in joy as she felt her belly expanding. Max’s cock was still plugging her hole, and could be for a while longer as her pregnancy ensued. Her doggy teats became longer, and started to sag down as they filled plump with fresh milk for Jen’s new puppies. After 30 minutes had passed, Max was STILL knotted to his increasingly pregnant human bitch. Jen could now feel tiny forms moving and twitching inside her her expanding womb. Jen pinched one of her nipples and watched thick creamy milk drip out below her. At 45 minutes her breathing started to become strained and her belly ballooned out and bulged around her sides. Max was still lodged inside her at this point, and Jen was starting to wonder if she could just pull him out. She couldn’t reach her arms to pull out the canine cock still resting in her pussy, and didn’t have the energy to pull forward to get away from Max. Over the new 15 minutes, Jen’s body looked like she has swallowed a writing beach ball. Her puppies were ready, but Max was not as he was still knotted to his mate one hour later. Jen felt her water break and spill out around the cock, as her puppies began to travel down her birth canal. Jen started pushing hard, and felt the puppy push Max’s cock out of her pussy. The first puppy landed softly below Jen and started whining for food immediately. Jen took a quick breather, then situated herself on her back for the next of her babies. She pulled first puppy to her chest and it immediately latched itself to one of her many teats and began suckling on Jen’s milk. By the time everything was said and done, Jen had delivered a total of 12 puppies. She laid exhausted on her back as each of the puppies sucked her thick teats dry of all her milk. Max laid with Jen and groomed the babies as they watched their babies grow. This was better than she expected, was all she could think to herself as she lay in bliss with her new mate and their pack.