As Katy got up, she did not feel as much sexually satisfied as she had to be. The new part of her soul raged for more satisfaction.
Even as she could feel Cal's doggy semen run down her inner tights the mere view of his still fully errect cock hightened her already heavy arousal to a point were her human thoughts were erradicated by her new and undescribable animal lust.
"You're a great stud, brother", Katy whispered hard breathing, "and you deserve a great bitch." She'd be more then willing to sacrifice everything she had to be impaled by her brother's wet, hard doggy cock.
While Cal observed her every move with some kind of understanding in his animal eyes, Katy took the collar from his neck and held it in her hands for some moments.
Whatever she had been some days ago had been replaced with what she was turning into with every animal orgasm she experienced. The collar and the dildo had marked her with some curse that turned her into a lusty bitch part human and part dog - but every passing moment her resistance waned and only fueled her arousal. She wanted to be a bitch. She wanted to transform physically as well as mentally. She wanted to be her brothers bitch.
Without further contemplation, Katy put the collar around her neck and fastened the lock...