Action or behaviour that advertises that someone is a twat. Good examples are: posh white people that have dreadlocks, being vegan, going to any left wing demonstration, or getting offended on someone else's behalf.
Did you see the spoiler on that car? What a twatvert.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi