Say It

Master Blaster: Who... run... Barter Town?
Aunty: You know who.
Master Blaster: Say.
Aunty: Master Blaster.
Master Blaster: Say loud.

—Mad Max Beyond Thunderdome

If a former friend, former ally, enemy, political rival, or just someone you hate or like to make fun of wants your help, or a favor, or just to get in the clubhouse, why not make them grovel a bit before helping them?

Yah, so, make them admit that you rule, or make them do a silly dance. A form of Word Power.

Sometimes used by villains as part of trying to make a hero Kneel Before Zod.

Examples of Say It include:

Anime and Manga

Bleach: Yumichika's zanpakutou refuses to give Yumichika access to its power if Yumichika messes up the name. Since its power betrays Yumichika's divisional code of battle, Yumichika deliberately calls the zanpakutou by a name it loaths to take advantage of his sword's attitude.

Fan Works

From the Symphony of the Sword installment of Undocumented Features entitled Entr'acte: A Question of Faith, comes this little moment after a fierce competition in a video arcade:

They emerged an hour later to find Corwin and Utena drinking milkshakes and talking about cars at a table in the food court. Nall was up on the table, flipping through a comic book and looking bored.
"About time you guys got done in there," Nall griped as the two women approached the table. "Who finally won?"
Juri looked down. Kaitlyn looked smug.
"S-s-say it," she said. Juri didn't reply; she merely stood, head hanging, and gazed down at the top of the table. "S-SAY IT!" Kate snapped, grinning wickedly.
"... Kaitlyn's kung fu is best," said Juri in a small, beaten voice. Then she gave up the act, smiled calmly, and sat down, adding with sly good humor, "For now... "

Film

In The Goonies, Chunk is forced to do "The Truffle Shuffle" for the others to gain admittance.
In Homeward Bound: The Incredible Journey, Sassy requires Chance to say "Cats rule and dogs drool" before helping him catch fish.
In Mad Max Beyond Thunderdome, Master Blaster shuts off the (methane) power whenever his power feels threatened by Aunty, and forces Aunty to recite the phrase "Master Blaster runs Barter Town."
Tank Girl. "Just say it, 'I won', and the little girl lives."
Pulp Fiction:

Marsellus Wallace: In the fifth, your ass goes down. Say it!
Butch Coolidge: In the fifth, my ass goes down.

Escape from New York:

The Duke: What did I teach you?
President: Y-You are the... Duke of New... New York. You're A-Number One.
The Duke: I can't hear you!
President: Y-You... You are the Duke of New York! You're A-Number One!

Live Action TV

X-Files "The Unusual Suspects" (origin story for The Lone Gunmen), Langly refuses to hear Frohike's request until he says "Your Kung Fu is best," (a reference to one of Kevin Mitnik's cryptic taunting phone messages).
Turk makes JD say "I'm your biatch" every time he beats him at something in Scrubs.
One episode of Married... with Children focused on Peggy trying to get Al to say "I love you".
In Justified, Donovan points a gun at Quarles and demands that Quarles admit to killing his friend Brady.

Newspaper Comics

On one early Calvin and Hobbes strip, Calvin has to sing the following before Hobbes lets him in their treehouse:

Tigers are mean! Tigers are fierce!
Tigers have teeth and claws that pierce!
Tigers are great! They can't be beat!
If I was a tiger, that would be neat!
He can climb the tree without the ladder, so he got to make the password.
Hobbes: Go on, what's the third verse?

- This also comes up occasionally when they play Calvin Ball.

Western Animation

In the South Park episode "Scott Tenorman must die", Scott forces Cartman to sing a self deprecating song and dance "I'm a little piggy" in order to get his money back (and he still doesn't).