De pits

n.

A word to describe an appalling, dreadful, terrible, dire deed that someone did to another.

In use

Mickey: "Ah Paddy boy, wait an' I tell ye... she kicked me conkers and crushed me perry winkle when I broke it off with her." Paddy: "Jay boy, das de pits so it is!"

Let Lawrence Muck translate it to posh English for you
Lawrence Muck

Welcome to the finer side of slang. Would you like me to translate 'De pits' in use for you?

'Paddy, let me tell you, she kicked my conkers and crushed my periwinkle when I broke it off with her.' 'Goodness, old boy, that is simply dreadful!'