Traditionally, at Christmas Eve dinner, the eldest family member breaks off a piece of the opłatki wafer and says a blessing. The wafer is then passed around to other family members around the table, each of whom breaks off a piece and eats it. Our family does it a little differently; each family member takes a piece of opłatki and then walks around the room to other family members. We individually share a hug and a 'Merry Christmas' and each person breaks off a small piece of opłatki from the other person's wafer. Here are a couple of photos of my uncle showing my 3 year old son how to do it.