I agree with the level of stupidity suggestion. The word "twat" is slang for both a vagina and an idiot. It's used more commonly for the latter meaning and, in that context, in BrE, I would say it's not considered particularly offensive. I call people twats all the time - bad drivers, people who don't say "Thank you" when I hold a door open for them, my flatmate when he makes a really bad joke. On that basis, I would understand and accept "He's demonstrating a high level of twatage today". I might even spell it "twattage". I don't know. I've never written it down! I can also imagine something like "What a load of old twatage", rather than "a load of old rubbish/twaddle".