Use the five-spin slot strategy to play up to five spins at various slot machines. It's time to move on to the next machine if you receive non-0 wins. With the five-spin slot strategy, you are simply trying to get a taste of several machines rather than trying to win multiple times on one particular machine.
The phrase "meeting slot" is correct and usable in written English. You can use it to refer to a scheduled meeting time, or a time slot that has been set aside for a meeting or appointment. For example, "I have a meeting slot at 10:00 AM tomorrow.".