Sam

In Terry Pratchett's Going Postal he creates a variant of rhyming slang which does not in fact rhyme. However, there are still rules to the derivation of the slang words. For example a wig is called a prune. This comes from syrup of prune which is related to syrup of fig which does rhyme with wig. Can anyone make the connection between "cup-and-plate" and the phrase "He's a bit cup-and-plate in the head" which in context is implying that someone is a few fries short of a Happy Meal?

I have a couple of coasters from a band called Barleyjuice, a pan-celtic rock group from Philadelphia On them they have the phrase "Rest Priest Here", which obviously is supposed to mean that you should put your beer on the coaster. What's the story here? Is this an Irish phrase, one from Philly, or just a bit of slang made up by the band?