http://www.disboards.com/showthread.php?t=3014713
"walking a reservation" involves calling as early as possible.
if i want dec 25 for 7 nights, i would normally call on jan 25. but since it's a busy period, i could also call on jan 19 and book dec 19 for 7 nights since that is the first day i could call to book dec 25 (as the last night of a 7 night reservation). then i could call back on jan 25 to add the last 6 nights (more or less).