This was a great post. I may steal the "great dad" code.
Me and my husband don't have any code words that I can think of but we use a second language as our marital code. My husband is hispanic so he is fluent in spanish and I have been trying to learn. I have noticed that the phrases that really stick are the ones that I want to say to him when we are out and about and I don't want the people around us to understand us. Luckily for us the majority or our friends and family don't speak spanish so this has worked out well.