Snape sighed. A phial in soothing blue glass zipped down into his hand from a distant shelf. He unstoppered it, tipped his head back, and tapped three drops deftly into his own mouth.
Four cheers for a well-brewed Migraine Mitigating Mixture.
He restoppered the phial and banished it back to its shelf. "Just because I can," he replied in the sort of slow, painstaking tones used when making a point to a child, "doesn't mean I will ever do it to you in future. Or am doing now. Or have ever done in the past."