A classic childhood pastime for many is building a "blanket fort" or "pillow fort" out of pillows, couch cushions, blankets, and other bedding materials to make a sort of "clubhouse" or "secret hangout".
Fort building can be enjoyed by teens and adults, as well. Many parenting books even suggest that parents build one with their children as a bonding tool.
When an adult builds a fort in fiction, [...] [tvtropes.org]