[They could go out with him in human form, but she's noticed that he always seems to like it when the people they pass on the street pet him. And, well, they won't pet him as a man.

Hence the suggestion that he be a dog.

...also now she's petting him, so that's her real ulterior motive here.]

But how am I supposed to improve if I don't push past my limits? If I just keep doing what I can do instead of trying things I can't, I'll never get better.