While they were eating, Draco cast a muffliato and then a silencing charm right in Hermione’s face and then summoned Piskey, turned his back on Hermione, and had a quick discussion with the elf. Piskey clapped her hands together, looking delighted, and vanished. When Draco removed the charms, she opened her mouth to eviscerate him but hesitated as he grinned at her—that same one with the sparkling eyes and the dimple.