Prolific author and director John Waters is pushing the envelope with humor and free speech in all sorts of ways, including with his new book "Liarmouth," which he discussed with Sue O'Connell on Greater Boston.

Waters has observed that over time, American humor has changed, which challenges him to push comedy to the edge without going over. "How can I do it without falling over the cliff? And the main way to do it is you make fun of yourself first and I make fun of the things I love," he said.

Waters poked fun at politics and free speech issues, saying he believes in the "excess of free speech."

"I'm always trying to do the opposite thing and make fun of it, but that's how you make them look stupid, you make your enemy look stupid and that's how you fight a war — with humor," he said.

Waters has had much success in the arts including in writing, acting and directing. "I feel at home telling stories — to me, writing a book or making a movie, I feel equally at home in both those worlds."

Watch: John Waters on his debut novel and keeping things weird