As someone that uses the word Mongboard regularly, I can confirm that the actual definition of mongboard is 'an Internet forum where mongs spend too much time monging' I can also confirm one of the definitions of 'mong' is slang for someone who does something idiotic. The state of being 'monged' is being a vegative state usually as a result of consuming too much alcohol or drugs. I have to day Harry Kane does talk like he's monged.
So there we have it, stop getting your knickers in a twist and Jimmy D can retract my infraction points as I was right.