Damn straight that woman hates her. It's very much mutual.

"I suppose we could take her to the zoo," she says slowly, "...and leave her in the car..."

Eugh. On the other hand, it wouldn't be that hard to escape.

"That car's new, she's not sitting in it alone..."

Dudley begins to cry. Or rather, he scrunches up his face and starts wailing—he hasn't really had a real cry in years.

"Dinky Duddydums, don't cry, Mummy won't let her spoil your special day!" she says, flinging her arms around him.

"I... don't... want... her... t-t-to come!" he yells between huge, pretend sobs. "She always sp-spoils everything!" He shoots Dorea a nasty grin through the gap in his mothers arms. 

She gives him an unimpressed look in return.

...he's honestly shocked, but before he can do anything about it the doorbell rings.

"Oh, good Lord, they're here!" she says frantically and goes to answer the door.

Dudley immediately stops pretending to cry to welcome his best friend, Piers Polkiss, the one who usually holds Dudley's victims' arms while he punches them.

Vernon goes to greet them—

—and Petunia excuses herself and walks back to the kitchen. "Girl, come here," she tells Dorea, and goes to an out-of-the-way corner.

"Yes, Aunt Petunia," she says, and goes.

When she's sure no one else will hear, she turns a very stern face to Dorea. "I will be very, extremely put out if—any funny business happens. Do you understand, girl?"

"I understand."

Aunt Petunia squints at her and looks about to say something else, but thinks better of it, deciding to just return to the living room to talk to Piers' parents.

Soon enough they're gone and the Dursleys plus Dorea and Piers are to go to the car.

Dorea attempts to interact with the other inhabitants of the car as little as possible. That seems best for everyone, really.

Eventually they reach the zoo where Dudley and his friend were to spend the former's birthday. The Dursleys stop at an ice cream stand in front of the entrance and get large chocolate ice creams to Dudley and Piers, but before they can usher Drea away the lady inquires as to what she wants.

She is really tempted to order the same thing but today is not the day to provoke her aunt. She picks the cheapest thing--a lemon ice lolly--with her best beaming adorable-little-girl smile.

Uncle Vernon dutifully pays for it and doesn't even complain.

Into the zoo they go.

Dorea looks around with interest.

At lunchtime they eat at the restaurant, and Dudley throws a tantrum because his knickerbocker glory doesn't have enough ice cream on top, so Vernon buys him another one and Dorea's allowed to finish the first.

Ooh! Dudley's an idiot, this is lovely.

After lunch, they go to the reptile house. It's cool and dark in there, with lit windows all along the walls. Behind the glass, all sorts of lizards and snakes are crawling and slithering over bits of wood and stone. Dudley and Piers wanted to see huge, poisonous cobras and thick, man-crushing pythons. Dudley quickly finds the largest snake in the place. It could wrap its body twice around Uncle Vernon’s car and crush it into a trash can—but at the moment it doesn't look in the mood. In fact, it's fast asleep.