While I was in Up State New York mall last weekend, I stumbled upon an interesting book:
As someone who took university classes in Japanese, the transition from uptight formal speech, to this more informal-slang type of speech was a surprisingly easy transition. This is obviously not a replacement for real classes since you are learning phrases and not the ability to coin your own sentences, but for a last minute quick helper, this is great!
Not only does it give a chapter on the 'Language of Love', but more useful, everyday encounters such as greetings and casual conversation.
If you are pressed for time to read a whole book, let me assure you that this book is thin and easy to carry around. If this does not sound encouraging, just click on the above link, read the intro, and you would have learned a great deal about the language already.
(There were some things it did not state, like how some ways of talking make you seem lower in class, and I completely disagree with using anata for anyone but your husband/wife but otherwise, a very amusing hour going over the book)