Cal pushed Katy off of his dick, how nearly six months pregnant she could move so fast he didn't know. He saw coarse hair rising up from his forearms, felt his ears growing through his hair like Spock but twisting and turning. He was allergic to this bitch, his bitch, if he could get away the changes would leave making him human again.
Katy had been using the collar almost daily to ease the burden of being pregnant. More she was a dog running nude and free in the fields. Clothes were becoming like manners to her, used only when necessary. She wanted to be loved, not alone and Cal couldn't abandon her like this. Her nails turned into curved claws and she started to pace around on all fours, despite still looking like a woman.
Black fur began to sprout on her shaved pussy. It coated her quivering thighs as it thickened at her crotch. She could feel it pushing out of her, her flesh heaving as black hair grew out of every pore Like moss on speed fur racing up to over her butt and down her thighs as it spread to cover her bulging stomach. Small bumps started to appear on bare patches in the fur, her nipples for her litter. A small bump started to appear as her tail
She wanted the change, wanted to be loved and seeing Cal run away made her angry. Katy lunged at him and slashed at his back with her right paw/hand. The lacerations spread the curse through Cal's back as hair started to blossom across his back speeding up his transformations. He tried to fight it, ripping off his clothes as he started hunch over like a were-wolf complete with the elongated nose, ears and facial hair.
He ripped his pants off and exposed his doggie cock, they were part human/part dog. Maybe only the dildo and the collar could complete the transformation. Katy had tried to let wild dogs fuck her, but they knew she wasn't one of them. Only Cal was, only brother and sister were marked by the curse of the canine. He bent his sister over and shoved his elongated dick into her pussy. Katy still had breasts to fondled so he massaged them as he let his pure anger turn into lust. He bent her over a sink so hard her head broke the glass leaving a small trickle of blood from her forehead.
He pounded her hard, scratches drew blood from her body, but her thick body hair covered it up. Still fighting his animal lusts he pounded at Katy until he could feel his orgasm building, his balls started to tighten, his shaft stiffened as he shot another impregnating load into his sister, but at the last moment he pulled his dick out and blew his load across her back, splattering across the cracker mirror.