Sasha was not being entirely straightforward with her friend. She wasn't here to decide whether or not to stay permanently as a dog. She had already made that decision. In the years since her first visit, her life had come to revolve more and more around the short times she was able to spend as a dog. Being a dog just felt right, and being a human just felt increasingly wrong. People could barely smell anything! And they had no tails!
So Sasha had quit her job, said goodbye to her remaining friends, and turned her back on humanity forever. And embracing doghood fully meant going into heat, mating with a male dog, and bearing and nursing a litter of puppies--a prospect that called to Sasha. (Male dogs were so much sexier than human males anyway!) She hoped than her friend Jennifer would join her permanently as a bitch, but maybe it would take a few more visits.
So on the morning of the third day, when Sasha woke up with a strange, new feeling centered in her genitals, she barked with eager anticipation. This was it!