"What? I just shoved it at the nearest arse I could find." There, that had done wonders for his mood. Harry smiled at Draco, very entertained by his new colouration. "You look very pretty, Malfoy."

He said it sweetly and then he turned back to his own almost sparkly clean cauldron, feeling a definite sense of satisfaction. Nothing quite like knocking that arrogant git down a few pegs.