In the opinion of the Party of the First Part, the Party of the Second Part has behaved improperly. If the Party of the First Part is superior to the Party of the Second Part (and doesn’t expect to need their help in the future, or just doesn’t care) the Party of the Second Part gets abraded.
Wirebrushing is best suffered with the greatest possible silence and neutral posture. Mostly, don’t be submissive in posture, gesture, or speech – that tends to encourage the Party of the First Part to deliver further abuse. Do say “I’m sorry”, even if you’re not, because it costs you nothing (including self respect). Be polite, which also costs you nothing.
Sometimes a wirebrushing isn’t deserved. Get over that. It will all balance out, especially if, when you someday become the Party of the First Part, you try to remember what it’s like on the receiving end.