Cococay is RCCL's private island, and a very pretty little spot if you are actually able to get there. The ships stay a bit out at seas and you are tendered to the island for a day of fun. On our last cruise there in April, the seas were too rough and we could not tender over to it. Everything on the island can be purchased/rented by simply using your sea pass card. Jet ski's, trinkets, drinks, etc... RCCL actually does a really nice BBQ lunch for all guests there (chicken, ribs, hambers, hotdogs, etc...)
We always put our luggage out the night before by 10pm. The disembarkment process is really long, depending on what color your assigned and don't forget you have to vacate your stateroom by 7:30am!
Do you really want to be toting all your luggage around the ship as you wait for your color to be called... most waiting areas get pretty crowed fast.