Jacks

n.

Heard in Kilkenny, Meath, Galway, Dublin and Limerick

The toilet or W.C. Comes from Shakespeare's King Lear (II ii 74-6),

In use

I shall tread this unbolted villain into mortar, and daub the wall of a jakes with him.

Posh English

I shall trample this unprincipled scoundrel into mortar and plaster the lavatory walls with his remains.

Same phrase, other counties