Cosmo and Wanda went to the same high school together.
Apparently a lot of the students from Cosmo and Wanda's high school had lied about something personal and that they've been hiding the truth up until now. (For example, Luthor had claimed to the school he still does football but he reveals at the end that he now does ballet)
Timmy claims in this episode that his family have bladders of steel.
Juandissimo was unaware that Cosmo and Wanda were married prior to this episode.
The episode's title is a spoof of Truth or Consequences.
The owl that brings a letter wears a red-and-yellow scarf, which is a reference to Harry Potter (it refers to the Gryffindor House which is the house that the three main characters are in in the series).
Also, the owl could be a reference to Hedwig, Harry Potter' owl.
Luthor Lex's name is a parody of Lex Luthor the main enemy of Superman.
Timmy having to hold it despite needing to go to the bathroom.
Britney Britney saying random things.
It is said that there are no doors in Fairy World, yet doors have been seen and used by fairies all the time in episodes before and after this one. (ex. the doors at the Pointy Crown in This Is Your Wish)