What date does Christmas fall on every year? You guessed it, the 25th. And let's just say you enjoy a cake on Christmas. Hypothetically, if you're supposed to eat that cake on Christmas day and no one does, what is the logical thing to do with it? Right again, THROW IT OUT! A Christmas Cake is a 26+ year old female who has passed her prime. Signs that you have encountered a Christmas Cake are children, Hollister clothing, 19 year old best friend, 1997 Saturn SL1 w/ sun roof, etc. You get the point. See also cougar.
"Dude, I went to some party on campus last night. It was pretty lame. I thought there would be a lot of fresman hotties, but instead it was swarming with Christmas Cakes!"