The dilldingus (pl. dilldingi) is whatever you need it to be. Is it a naughty bit? Sure. A dumb person? Why not. Perhaps you need a word to describe a new clothing line—try dilldingus. This is a new, happening word that is just catching on.
"I asked that guy to show me his dilldingus; he punched me."
"Whatta dilldingus. You are so dumb."
"Your look is completely dilldingus."