Simpleton that I am, I suggest it's an event which is, or promises to be, a real stoush. Lots of heavy hits which knock the slobber out of the combatants.

Met some US'ns a while ago who used the term "slugfest" to describe an encounter between two groups of people. I honestly thought they were using "slug" in the UK vulgar sense (ie unit, member, tool, wizzer, dangly bit etc etc) - ie the event was going to be a sexual orgy. Later realised they expected it to be an orgy of violence!!

stales