When the kids hear Lily curse, they are terrified they have been a bad influence on her, and decide to change their behavior for the future.
Rita and Lynn Sr. are heading off to the mall, because Dr. Shuttleworth of the daycare academy, is coming to interview Lily, and Lynn Sr. needs a more appropriate tie. Once they head out, Lynn changes the TV channel because Dessert Storm is on right now, and Lily suddenly exclaims "dannit". This causes the siblings to gasp in horror, because they think that Lily had just said the "D" word. The siblings fear that Lily learned the word from them, because in past experiences, the kids have gotten into some predicaments that lead them to crying out the "D" word in anger, and Lily was there to witness them saying it. The siblings realize that if Lily were to exclaim that word in front of Dr. Shuttleworth, Lily won't gain access into the academy Rita and Lynn Sr. have signed her into. Lincoln says he has an idea on how to make Lily forget she ever said that word.
The plan is set into action. Each of the siblings are tasked on reenacting the action that led them into saying the word. Throughout all of these, their faces would turn red, and are on the verge of saying the word, but they would say something else in hopes that Lily would mimic them. After nearly an hour of doing these actions, the siblings believe that Lily has forgotten all about the word. At that moment, Rita and Lynn Sr. arrive back, and begin prepping things up for Dr. Shuttleworth's arrival. One of the things they do is set a tray of snacks on the table. Lily tries to get one, but the siblings tell her not to eat them, causing her to exclaim "dannit" again, making the siblings realize that the plan didn't work.
Dr. Shuttleworth arrives, and is ready to interview Lily. Dr. Shuttleworth gives Lily several things to play with, such as a hardware set, a guitar, and a ball, but the siblings fear that Lily would do something that lead to her yelling out the word, prompting them to confiscate the toys. When the kids become too bothersome with their meddling behavior, the parents tell the kids to leave, but Dr. Shuttleworth tells them that they should leave too, as she just wants to be with Lily. The siblings huddle up, and says that they need a plan to get Lily out of the room. Lincoln suggests on making Lisa take Lily's place, because of the fact that she wears a wig after a nuclear experiment gone wrong, and wearing dentures. The siblings take Lily away under the guise that she spoiled her diaper, and put Lisa, disguised as Lily, in Lily's place. However, Lisa begins displaying some of her smart aleck attitude, like painting complex formulaic equations, doing an impressive xylophone solo, and able to tell Dr. Shuttleworth what type of condition her eyes are in, just by looking at her glasses. This prompts Luna to tell Lisa that she needs to act more like a 1 year old, which she does by intentionally soiling her diaper.
Later, Dr. Shuttleworth is done interviewing Lily, and concludes that due to the things Lisa did, she's allowed into the academy. Just before Dr. Shuttleworth leaves, she takes the snacks on the table with her, causing Lily to exclaim "dannit". Everybody is left horrified at this action, and the kids begins pleading to Dr. Shuttleworth that Lily didn't mean to say that word, and say that they've been a bad influence on her. Dr. Shuttleworth, however, laughs at this, saying that Lily didn't say the "D" word, she was actually saying "doughnut". Dr. Shuttleworth gives Lily a doughnut, and leaves. While Rita and Lynn Sr. begin cheering at the fact Lily got accepted into the baby academy, the kids begin cheering at the fact that they weren't a bad influence on Lily. However, as they cheer, Charles comes by, and snatches Lily's doughnut, causing Lily to cry out an actual curse word (which is bleeped out) in fury, causing the family to look on, and gasp in sheer horror.
TNA - Leni saying "Delete" repeatedly could be a reference to Broken Matt Hardy's catch phrase
Grawlixes - The random characters used to cover up Lily's swearing in the title card are known as grawlixes, which are "typographical symbols standing for profanities, appearing in dialogue balloons in place of actual dialogue".
Teletubbies - Lily's appearance on the title card resembles the Baby Sun from this preschool show.
Sesame Street - When Lynn Sr. mentions a tie with a bird playing the saxophone, it is a homage to the Sesame Street character "Hoots The Owl."
Wii - The game remote Lincoln was was using in his flashback of yelling out the "D" word highly resembles a Wii Remote.