Backwards

Occasionally isn't the right word. Shin-chan shows his butt all the time. He also routinely shows his genitals (His Mr Elephant Dance). Costumes of Shin-chan are basically just a plastic butt.

It's likely not Shin-chan's butt though. His face is one of the other molds and even though he's 5 years old, he uses highly inappropriate language and often reacts to older/adult women in an inappropriate fashion. Shin-chan is one of those shows that seems like it could be a kid's show, but totally isn't. So, they wouldn't even attempt to hide the fact that this is a lady's backside that Shin-chan is reacting to.

I like big butts and I cannot lie- wait, WTF!

Totally agree with Robert. I used to watch it way back when I was still young. Didn't place much thought on how he just randomly shows his butt or how he just calls his mother by her first name. The show's funny (in an inappropriate way) for an adult but for kids, it's just not good. The only cute thing in that show was his dog, Shiro. It's not surprising to have this kind of treat associated with Shin Chan.

oh boy- a jello twerk...