A typically Northern Irish expression also spoken as "face as long as a Lurgan spade" meaning to look miserable or long faced.
One theory about the origin of this expression is that a “Lurgan spade” was an under-paid workman digging what is now the Lurgan Park lake. Another theory is that it is a translation from the Irish language lorga spád meaning the shaft/shin of a spade.
Upon observation you would say...
Euphemism describing the act of defecating, metaphorically speaking. Otherwise known as taking a good hard shyte for oneself. This particular expression is used when the excrement is of a particularly large and solid nature.