I think I'd skip it on Christmas unless you knew it was going to go over well. How about the Winter Solstice, December 21st? "Honey, you know how today is the darkest day of the year? Up at the North Pole, they don't even see the sun all day. Speaking of places where the sun don't shine..."
Of course, you might want to be at least arm's length away from her at the time, with a clear path to the doorway.