Corvina opens her own thumb with a silver knife and lets one drop fall, and then passes the knife round the table.

Malfoid does it without hesitating. Mione does it slowly and looks at you while she does it. You do it last and your hand is steady, which surprises you.

Nothing happens for four seconds. Then it arrives all at once, and it is not like being told. It is like being handed four sets of weather.