Call and have it attached to your reservation.
Mousekeeping will set it up for you, when your room becomes available for occupancy.
They will make it up each day for you as well. If you are lucky; you might get a mousekeeper who enjoys doing some silly stuff for you as well.
We went last year with an infant, and Mousekeeping put the blanket draping down over the side and hung all of his stuffed animials down the blanket, like they were trying to "escape." It was pretty funny!