"Thanks," said Kiri. She piled sausages onto her plate. "Oh, and have you heard," she leaned in for an encore, grinning wickedly, "of Care of Magical Creatures? We'll be out all day... in the cold... looking after beasts that'll take your hand off if you're not careful. That's what I call unhygienic." Of course, Kiri was not particularly fond of the subject herself, but the boy was going to find that out anyway, and she was in no rush to tell him.
She decided it was time to play nice again. Her smirk became a friendly smile. "Anyway, don't worry about it. We'll take care of you. I'm Kiri Starstalker."

Piercing a sausage with her fork, she smiled at Nancy as well for good measure. She'd just taken her first bite when... What was this? Was there a feeling of evil in the atmosphere? Had the air suddenly become cold? Did the sausage taste only half as good as before?
Yes, Professor Kazimeriz, hunched over his cane like an old tree, had joined them at the table. Kiri chewed and swallowed hurriedly, nearly falling off the bench in surprise when the professor addressed her - in what she could only describe a friendly tone of voice!

She blinked. "Oh, er... good evening, Professor," she said, smiling uncertainly and hoping very much that her mouth was empty and that no bits of sausage were clinging to her teeth. "Um, a-a cleansing charm?" she repeated, very much wrong-footed. "Of, er, of course, Professor." Kiri got up and pulled out her wand. "Don't move," she advised the boy and pointed the wand at the bench. "Tergeo!" She moved her arm up and down to clean the entire surface.
"There." She peered at the bench. "It doesn't look any different, I have to say, but you could eat your dinner off of it now. Not that I think you'd want to." She slid into her seat next to Nancy.
Feeling very bold, she turned to the old professor and asked, "Did, er, did you enjoy your holiday, Professor Kazimeriz?"