"Holy cheese" is a sideways reference to the works of David Willis. Characters in his comics swear to cheese all the time - though he doesn't usually play the Robin angle. I guess it's possible that he's been consciously avoiding it, since one of his characters is called Robin, and Batman is one of his major shticks. Maybe something cries out inside with every strip he writes, to have some character scream "Holy cheese, Robin!" Maybe even in the context of some swiss cheese. But somehow he rises above it. He is truly an example to us all.