"Dear me," Mr Malfoy said in a soft, mocking voice, "What's the use of being a disgrace to the name of wizard if they don't pay you well for it?"
"Well then!" Mayumi chirps, in a calm but cheerful tone, "We'll just have to work harder. I mean, look how well they're paying you, mister!"
She blinks with wide, innocent eyes and let her words marinate in the air... And three seconds later saw Fred and George howling on the ground.