@Amana09  
mouthpiece is a tag used for when an artist has a character stating an opinion of some kind for them, with the image’s only intention being to validate that opinion through the character.
 
It doesn’t apply when the character in question directly represents the artist, as is the case here.

@Amana09  
It’s when you slap a message on a pony image, as if to imply it is the point of view of that pony, even though it’s really just your point of view. It can often be annoying, as it is often used just to force-feed people the opinions of the creator.
 
https://derpiboo.ru/search/index?q=mouthpiece

@klystron2010
 
Mouth piece?

@Jarkes  
Indeed, since that is pixelkitties’ ponysona, it’s not a mouthpiece.

It’s images like this that keep me from filtering the mouthpiece tag.
 
(Yes, I know that tag is no longer on this image, but my point still stands)

Except for anyone who has the audacity to criticize the show runners. Heaven forbid that.

This is true I love this(I just wish Howard stern understood this):/

@Background Pony #9F33  
And how are you better if you use autist as a pejorative termm.Both side are guilty

Pixelkitties says it like it is.
 
As she tends to do. :)

Bonds weaken with time, I see.

Lovely picture, a tad confused as to why it’s featured though.

@Cyborg_pony  
Nice conspiracy theory.
 
If ponies are for everyone, then they are for SJW’s, too. Full stop. Quit being a hater for once.

@SeraphimDawn  
A slug.

Pixelkitties is godlike.

Stay posi.

This pony vaguely resembles Alex Vause

@HighRollerHydra  
A golden octagon with a jian in the middle.

@SeraphimDawn  
Speaking of, my cutie mark is three white, fluffy clouds.

@HighRollerHydra  
 
Yes…

@SeraphimDawn  
Lest they be teased by Diamond and Silver.

@hip-indeed  
In otherwords, they still haven’t found their cutie marks yet. We’ll be glad to help.  
Whether they like it or not  
Nothing shall remain un-ponified.

@RainbowDash69  
Haterade…gonna have to use that sometime.

@Jackarunda  
part of the cutie mark it is supposed to be original
 
like the ponies of olden times