Someone who only goes to church on Cristmas and Easter
that boy hasnt been to service all year, he's a creaster
One who attends church exactly twice per year, on Easter and Christmas, resulting in overcrowding. Necessitates regular churchgoers to arrive 45 minutes earlier than normal in order to find a parking space and a seat.
Wife: Honey, get the kids ready for church.
Husband: But it's forty five minutes early.
Wife: I know. It's Easter. If we don't leave now, the creasters will get all the good seats.
People that only go to church on Easter and Christmas.
There was nowhere to sit at mass 'cuz of all the creasters.