"What are you doing in my house, Potter?" "You're mom"
Draco: "WHAT?!?"
Harry with most shitiest grin on his face: "Your mother, that's what I'm doing here."
Draco's face goes from pale to purple: "Wait till my father hears about this!"
"I already did, son" Lucius said from the corner, sitting in a chair with a class of wine.