At the start of the show, Eddie changes his "steps back in amazement" catchphrase to pretend he's trodden in something unspeakable, making an "eurghh!" sound. He quips "I didn't do that in rehearsals" as his ad-lib noticeably makes Syd struggle to keep a straight face.
Around 23 minutes in, Eddie steps off a surfboard to speak to Kirsten Cooke, and momentarily stumbles, causing them both to chuckle, and Eddie tries to keep a straight face. However, it is also entirely possible that such "mistakes" were deliberately rehearsed and included to generate extra laughs.