"I have a WHAT?" Draco choked on his drink.
"A sister," Narcissa repeated calmly.
"I mean, I heard you the first time, but I have a WHAT!" Draco gasped, desperately trying to extract an ice cube from his trachea.
"I don't know what to do," Naricissa said, sighing, and flicking her wand lazily. The ice cube flew in a perfect arc back into Dracos glass.
"Thanks, but no thanks," Draco said, delicately plucking the ice cube from his glass. Narcissa looked at him curiously. "I mean, now that I know where it's been, it's not really s though I want it now, do I?" he continued reasonably.
"Are you talking about the ice cube or your sister?" Narcissa asked in a dangerous tone that could attribute to Professor McGonagall on a bad day.
Draco glanced at his mother's face. "The ice cube," he intoned carefully. "Definitely the ice cube."