If you cannot physically leave, claim the backyard. Or the balcony. Or a single park bench. Pretend you’re on a safari, observing the wild creatures of your own family through a window.
Take a book, a thermos of something spiked (or just hot chocolate), and a blanket. You are not hiding. You are "enjoying the winter air." It’s a noble lie.
The key to surviving Christmas is knowing where the exits are. They’re metaphorical, literal, or just a movie theater seat. Go forth. Eat a spring roll. Pet a bison (from a distance). And remember: no one ever said, "I wish I’d spent more time cleaning the kitchen on December 25th."