Susan barely could keep herself from laughing at the voice and pose Tony seemed to take on as he sang the song. Her smile was brighter than the Chesire Cat's by now, her frame more relaxed next to his despite the oddity of the situation. He easily covered her flaws to an extreme and she was only grateful for it.
The piano keys halted and the music faded away with the last note. He became just Tony Stark again. "Very nice performance", she said with a shake of her head. "I like it".