When stopping by the three-story shop, and get swept away in the near-replication of the set in the movies, be sure to adopt a Pygmy Puff - creates of the Weasley's own making.
One of them is seen cuddling on their sister Ginny Weasley on her passage to Hogwarts. Upon purchasing your Pygmy Puff make sure to let the cashier know you're officially adopting him / her.
You'll be in for a treat with an official adoption announcement to the rest of the store. Your name and as well as your new furry friend are given a round of applause. Take a bow and enjoy your adoption!