In this case "CD" stands for Cruise Director not an actual audio CD. What CruiseDad was referring to is called (on Carnival) the "Port Chat" normally held the day before you get to your first port. Sometimes its called the Super Shopper discussion too. But basically, the cruise director will host the seminar (for lack of better terms) and they go over what to expect at the port... getting on and off the ship, what stores they recommend, the Port Chats also go over the excursions available and provide more detail than what is available on-line. Thos are very helpful for first timers because you can better choose which excursions you may want to do since there are normally a couple that sound fun and you normally can not do more than one unless they are 2 short ones.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise, Magic 1/14, Freedom x 2 6/14
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013