What is the origin of this facial expression with one's tongue sticking out?


I've seen this expression probably a dozen times in anime and manga. There are
many variants, but they all have the character's tongue sticking up out of the
side of their mouth. Their eyes are also typically big and sometimes in the
shape of a backwards の character, or sometimes winking. Here are a few
examples, though there are many more:

**Bakemonogatari:**

![enter image description here](https://i.stack.imgur.com/J26P4.png)

**Clannad:**

![enter image description here](https://i.stack.imgur.com/FHs0L.png)

**Tonari no Kashiwagi-san:**

![enter image description here](https://i.stack.imgur.com/c50O6.png)

What is the origin of these expressions? Are they referring to a particular
art style or character?




All of these faces are direct parodies of Fujiya's [forever 6 year
old](http://www.fujiya-peko.co.jp/pekoworld/profile/index.html) mascot, Peko-
chan:

![It's Peko-chan!](https://i.stack.imgur.com/V62ew.jpg)

Peko-chan was created in the 1950s is probably the most recognized character
in the Japanese confectionery world.

In Japan, showing one's tongue can be used to express one's feeling
embarrassed at making a mistake. It's often times meant to be childish and
regarded as cute. There are no solid references connecting the behavior to
Fujiya's mascot, but some believe the behavior is popularized by children
imitating Peko-chan.

![Nyaru References](https://i.stack.imgur.com/eCpz8.jpg)




All of these faces are direct parodies of Fujiya's [forever 6 year
old](http://www.fujiya-peko.co.jp/pekoworld/profile/index.html) mascot, Peko-
chan:

![It's Peko-chan!](https://i.stack.imgur.com/V62ew.jpg)

Peko-chan was created in the 1950s is probably the most recognized character
in the Japanese confectionery world.

In Japan, showing one's tongue can be used to express one's feeling
embarrassed at making a mistake. It's often times meant to be childish and
regarded as cute. There are no solid references connecting the behavior to
Fujiya's mascot, but some believe the behavior is popularized by children
imitating Peko-chan.

![Nyaru References](https://i.stack.imgur.com/eCpz8.jpg)

