As soon as Katy had the collar around her neck, she felt the additional surge of animal lust she had come to count on from it. She watched Cal, the magic of the collar removed from his body, begin to transform back into his human self. She quickly began fucking herself with the dildo, and in an instant her legs grew out with fur, the nipples appeared and she began to take the shape of a dog.
Cal, still hairy and partially canine, leapt at her and began something between licking and kissing with his half-dog sister. Their paw-hands groped each other as they enjoyed these fleeting moments when they were bothin the ame state, somewhere between human and beast.
Soon, however, Katy finished her transformation, as did Cal, and the thin but toned young man stood over his sister. The dog looked up at him with human comprehension in its eyes, and took one quick lick at his still semi-erect cock.
Cal bent over and began patting his sister and scratching her behind her ears, while his other hand pulled the dildo out and began fingering her wet dog pussy.
"Jeesus, sis," Cal cried. "Where the fuck did you get these things! I never... I mean, I've been into some kinky shit, but this is like a whole other fucking planet! I had no idea sex could be..."
Katy yelped at him and turned, her tail up in the air, her pussy engorged. She turned again and nuzzled her brother's crotch, licking at his balls."
"Well now that you're my bitch, Katy, I'll give it ti you again."
Cal knelt behind the dog, his sister, and slid his penis into her dripping dog pussy. She whimpered quietly as he began to ride her.
"You like me fuckig you like this, you bitch?" he taunted. Katy yelped and let out a soft howl. He rammed his thick cock deeper into her bitch cunt, grabbing the hair on her hackles to push into her harder. He slowed down every few minutes to keep himself from cumming as he jammed himself deepr into Katy, his sister, this bitch in heat he was riding.
With a huge moan he shot his semen into her, collapsing across her back.