big mouth 

used in reference to somebody who likes to spread gossip, or who cannot keep a secret

His ex-girlfriend told everyone that he had a small penis. When he found out, he just said that she had a big mouth.

big mouth by yorrick hunt January 23, 2008

Porky Mouth 

Someone who has a foul or smart mouth.

This can be heard on That '70s Show by Debra Jo Rupp's character Kitty Forman.

Red: Oh, shut up, that’s it, I have had it! You know what this means? More discipline!

Kitty: No, no…

Red: Oh, yes. Play time is over.

Kitty: Oh, stop saying that! Your cracking down is not working.

Eric: Hell, I could’ve told him that a week ago.

Kitty: Now is not the time to be a Porky Mouth. Red, I want my house back.

Porky Mouth by J. August Quander August 13, 2010

Andy's Mouth Surprise 

Sited in Parks & Rec, Andy's Mouth Surprise is when you take Skittles and put it between two Starbursts.

I love Andy's Mouth Surprise because it's nice because the flavor of the Starbursts really bring out a similar flavor in the Skittles.

Andy's Mouth Surprise by ronfksldaingswanson August 7, 2012

Nap mouth 

The bad taste in your mouth just after waking up from a nap.

"*Yawn* Man I just woke up and now I have nap mouth, god damn."

Nap mouth by Keroberos November 17, 2006

downtown mouth 

Slang for vagina, so named for its resemblance to a mouth.

My boyfriend won't go near my downtown mouth when I'm on the rag.

downtown mouth by OhBrother56 November 4, 2009

Goose mouth 

A bitch with a disgusting fowl* mouth that wants to sink all 9000 teeth into you like a stanky hoe.

That goose mouth needs to go home and take a bath in some listerine.

Goose mouth by Gagglegurl July 10, 2015

Muma mouth 

A term used to describe a person with very visible gums over their incisors and canines when they open their mouth. The term was popularized because of Overwatch League’s player Muma, who plays for the Houston Outlaws, and his large gums.

“Bro, did you see the new student in class today? She got wicked muma mouth!”

“I was giving a presentation at work and I kept getting distracted because the person sitting in the front had muma mouth.”

Muma mouth by tsukemen May 16, 2019