DICK DICK DICK is a reference to an anecdote from high school that Lars discussed on an early episode.
One day in high school when Lars was in the computer lab with his friend Daniel, he introduced the latter to Wikipedia for the first time. Daniel expressed surprise that supposedly anyone could edit any article (which was true at the time). He proceeded to vandalize a random article by adding the words "DICK DICK DICK" to it. Lars and Daniel found great humor in this act, as expected from two immature teenage students.
Lars has repeatedly stated anxiety that someone would vandalize the wiki for the show by adding something like "DICK DICK DICK" to it, and has thus pre-emptively added it to the front page.