She had been teasing herself with the idea for months, watching the big male mastiff named Rex pace the backyard with his heavy balls swinging and that thick red tip peeking out whenever he got excited. At twenty-three she knew exactly what she wanted, and tonight the house was empty, the doors locked, and Rex was inside with her.
The moment she stripped naked on the living room rug his nose went straight between her thighs. His hot tongue dragged up her slit in one long, rough lick that made her knees buckle. She dropped to all fours, ass up, and spread herself wider for him. Rex mounted without hesitation, his powerful front legs clamping around her waist, claws scraping her skin as he thrust. The first jab missed, sliding along her ass cheek. The second hit home.
His cock punched into her pussy in one brutal shove, thicker than any human dick she had ever taken. She cried out, the stretch burning, but she pushed back anyway, wanting every inch. Rex growled low and started pounding, his hips jackhammering with animal speed. Each thrust forced more of his swelling cock inside her until the knot began to press against her entrance, stretching her even wider.
She moaned filthy encouragement, “Fuck me, boy, knot that pussy,” and Rex answered with harder, wetter strokes. Her juices ran down her thighs as the knot finally popped in, locking them together. The pressure against her g-spot was relentless. Every time he tried to pull back the knot tugged inside her, sending shocks of pleasure straight to her clit.
She reached down and rubbed herself fast while Rex kept rutting in short, powerful jerks, his heavy balls slapping her.
The orgasm hit sudden and vicious. Her cunt clamped around the knot, pulsing, and Rex let out a sharp bark as he came. Hot, thick spurts flooded her, so much cum it leaked out around the seal of the knot and dripped onto the rug. She stayed locked with him, shaking through aftershocks, feeling every throb of his cock still pumping inside her.
When the knot finally softened enough to slip free, a flood of dog cum poured out of her stretched hole. She rolled onto her back, legs open, and let Rex lick her clean, his tongue lapping up the mess he had made. Already his cock was swelling again, red and glistening. She smiled, rolled back onto her hands and knees, and presented herself for round two.
