Why is Santa’s sack so big?
Because he only comes once a year.
Santa's Big Sack
Explanation
Explain Bear
Ho, ho, hold on there, buddy! You're askin' why Santa's sack is so massive? Well, it's a blue-humor play on words, see? It's insinuatin' that Santa only "comes" once a year, like, sexually. I bet you're the kinda guy who thinks reindeer games are just about flying, huh? Keep those ears open and maybe you'll catch on someday!