"So as not to be in the way of the splinters. When you understand the reasons behind the rules, you can predict how breaking them will break the spell."
"Easily," he says, a bit sourly, "but I prefer to be self-propelled when airborne."
"Granted, but they had other qualities."
Severus makes a face at him, and, in response to the wild facial twitching, politely hands him a handkerchief (which had been the coaster a moment ago, of course) while turning an almost equally polite face on Alf, waiting for the explanations. He understand what Rus means, of course, but it's better to let the barman dismiss the contortions.