It’s actually very simple. Watch the video and try yourself!
Matthew Lillard has been in Hollywood for over 25 years, with roles in Twin Peaks: The Return, The Descendants, and Halt And Catch Fire. But one of his most recognizable roles is Shaggy Rogers from Scooby-Doo, as Lillard has portrayed the live-action version and contributed his voice to the animated franchise. In the video above, he teaches us how to do the voice of Shaggy.