Simply put, this is any situation where a character has to force a smile or a please/thank you despite not really wanting to do so.

A few examples:

1) Character A will demand something from Character B. Character B refuses to oblige their request until Character A says "please". Character A begrudgingly does so, and only then does Character B perform the requested action. This is commonly seen between parent and child, though it can occur between adults (typically for comic effect).

2) Character A will want something from Character B. Character B refuses to give it to Character A until they give them a little smile to show their appreciation. Typically, Character A will put on a very forced smile.

It's most common in sitcoms, but can appear in dramatic works occasionally, such as if a villain is trying to smugly exert their power over the hero.

----
!!Examples:

* Series/EverybodyLovesRaymond: In "Hackidu", Ray is impatient to get out of Russell's shop with the Scramisaur card, but before Russell will let him have it, he demands, "Let's have a little smile." Ray struggles to force a smile, and after Russell says, "That's what it's all about, man", he says he owes him well over $200 for the purchase.
** In "The Christmas Picture", Ray tells Robert to get over into the picture.
--> '''Robert''': What?
--> '''Ray''': Get over there.
--> '''Robert''': "Get over there..."
--> '''Ray''': ...Please?
--> '''Robert''': There ya go, Raymond. You'll find a little courtesy goes a long way.
* WesternAnimation/TheSimpsons: A variant occurs in "Black Widower" when Sideshow Bob is chewing out a hotel bellboy:
--> '''Sideshow Bob''': I WANTED A ROOM WITH A FIREPLACE, YOU BLASTED MONKEY! (realizes Selma is capturing him on camera) Oh Selma dear... I was just chatting with my good friend... (looks at his name tag) Dennis! Now, smile for the camera, there's a good lad! (Dennis struggles to produce a nervous smile)
* WesternAnimation/TeenTitans: Robin is being forced to take a supervillain's daughter to her prom.
--> '''Kitty:''' And would it kill you to smile?
--> (Robin forces a [[TechnicallyASmile painful-looking rictus]])
--> '''Robin:''' Maybe.
* Subverted in ''Literature/TheDresdenFiles'', where Harry is trying to negotiate a deal with local crime boss Johnny Marcone.
--> '''Marcone:''' Say "please".
--> '''Harry:''' Please...
--> '''Marcone:''' Say "pretty please".
--> '''Harry:''' Pretty please...
--> '''Marcone:''' Say "pretty please with a cherry on top".
--> '''Harry:''' [[CrowningMomentOfFunny Fuck you]]. *hangs up*
* ''Series/{{Farscape}}'' however plays it straight, when John Crichton finally agrees to give Scorpius the wormhole weapon he's been obsessed over for years. John goes all the way to "pretty please with a cherry on top" with Scorpius repeating his words without hesitation.
* Subverted in one episode of ''{{Rugrats}}'', where Angelica has taken a ball from Tommy, who wants it back.
--> '''Angelica:''' Ask me nice.
--> '''Tommy:''' Give me my ball!
--> '''Angelica:''' Say "Pretty please with sugar on top."
--> '''Tommy:''' Give me my ball!
--> '''Angelica:''' Say "[[HypocriticalHumor Angelica is the nicest]], prettiest, best person in the whole wide world."
--> '''Tommy:''' [[PunctuatedForEmphasis GIVE ME]] [[RuleOfThree MY BALL!]]
* ''Series/StarTrekVoyager''. In "Message in a Bottle" B'Elanna gives Seven of Nine a lengthy tirade on how rude she is, not even delivering common courtesies like "Thank you". Later Seven zaps unconscious an annoying alien who's giving them trouble.
-->'''Seven:''' It was a mild shock. He will recover. He was not responding to diplomacy.
-->''(Captain Janeway {{Death Glare}}s at Seven and storms out)''
-->'''B'Elanna:''' Mild shock, huh. ({{beat}}) [[ArsonMurderAndAdmiration Not bad.]]
-->'''Seven:''' Thank you.
----