He makes wearing diapers normal.

It's the diaper, rather than any other aspect of being a baby, that James really enjoys, so he decides to make wearing diapers acceptable in public. However, he refrains from making it normal, so that it's still exciting and arousing for him to be wearing it. As an afterthought, he also wishes for there to be changing stations in public places, where he can go and have his diaper changed as if he was using a public restroom.

When James looks around his room for signs of a change, he notices very few, until he looks inside the draw where he normally keeps his underwear. Instead of the range of boxers he had before the wish, there's now only diapers, lined up and sorted by type; different levels of absorbency, different types, and different colours!

In the end, James chooses one with a medium absorbency and a blue pattern, and pulls it on, noticing that it was the perfect size for him. Now it's time to go about his day.