get ones Irish up

from The Collaborative International Dictionary of English v.0.48

Irish \I*rish"\, n. sing. & pl.
   1. pl. The natives or inhabitants of Ireland, esp. the Celtic
      natives or their descendants.
      [1913 Webster]

   2. The language of the Irish; also called {Irish Gaelic} or
      the {Hiberno-Celtic}.
      [1913 Webster +PJC]

   3. An old game resembling backgammon.
      [1913 Webster]

   {get one's Irish up} to become angry.
      [PJC] Irish American