Dear Hungry Hungry Hippo Grandmaster, (love this by the way)
You can make a reservation for a lady at any time. Just call the office and let them know who, when and at what time. I would suggest also emailing the ladies that you are interested in to confirm schedules. Just because a day seems quiet does not necessarily mean that we are not busy. Keep in mind, all the naughty fun happens behind closed doors, not in the bar.