"Did she," he breathes murderously, and is a half a breath from demanding to know who the hell this Teddy is and and what he has to do with anything, and more importantly who scooped him, in a most uncivil manner, when he remembers the last time he felt this way.
'94. '94, with Lupin's DADA curse prickling under his skin and harrowing his nerves more every day, so strong with the weight of months that every breath he heard was a kettledrum, every footfall a siege engine, every suspicion a certainty, every degree of castle dampness its own seething, reeking swamp with tigers in the reeds. Building every day until he had not only embarrassed himself and his House, not only done necessary things in completely unnecessary, out-of-control ways, but thoroughly destroyed his credibility with Fudge, which they could really have used the next summer, after the Tournament.
But it's no good just recognizing the consequences when the feeling overtakes you. So he draws himself tight, pale and cold and stiff, states, "If you will excuse me a moment," and stalks past Miss Weasley into Lucius's washroom before he does anything more stupid than he's actually planning.
The soundproofing and so on to layer on top of what Lucius has undoubtedly put down, the transfiguration of this and that into a mirror in the right place, a wooden bit, and one of his sleeve straps binding his wand to his hand; the spell itself until his nerves are buzzing only with the overstimulation of a trembling fatigue, the overwrought heat of his skin subsided into clamminess; cold water on his face and arms and a bit of a think; restoring the bathroom and taking his own precautions off it; a few neatening-up charms. It takes some minutes.