So what is pepero? Pepero is a breadstick-looking cookie-stick usually covered in different flavors of chocolate. The cookie is more commonly known in the west by it's japanese name of Pocky-stick.
Why pepero-day? 11.11 - a date which in itself looks like a pack of pepero sticks. The original intention was that you would give eachother pepero sticks as a symbol of the hopes of growing tsll as a stick. These days it is mostly a commercial holiday, and the custom is to give a box to friends or coworkers.
People appreciate to get one, bt your are not considered rude if you don't give them out to everyone.
Last year i got one box from one of our contractors, this year one of my co-workers bought a box each for the girls, i myself bought for my girls at work as well. By all means, you can even buy one for yourself.
Enjoy this relaxed "holiday" and who knows, eat enough pepero sticks and maybe you will get taller...?