One sweaty afternoon I was with Freddie, just the two of us there, I think. We did a lot of those things: we did the tap dancing with thimbles on the fingers on the metal bit on the top of the desk and I did a little brass section and Fred was doing woodwind with his mouth. It was like experimentation - we were sort of laughing at the same time, but I think turned out rather well. It was meant to be cod, and cod it was!