Simon Fraser says:

Right I’m going to try that on my 2 year old! She’s seen so much undubbed Miyazaki that the language won’t be a problem.

Si.

Trip Bakun says:

This is a video from Shimajiro, a Japanese cartoon used to teach young kids about Japanese culture when they are small. My kids, who are half-Japanese, love all of the Shima-chan videos that we have!

Anyways, I think that the portion of the video you are referring to is when Shimajiro says “onaka ga muzu muzu suru!” Muzu muzu is a Japanese onomatopoeia (and yes, I did have to look the spelling of that word up in a dictionary!) and in this context means something along the lines of “I feel like I have to go to the bathroom.”