The high five was an Earth custom, and a gesture shared by two people to congratulate themselves on a job well done. Ace explained to Narvin that they "clap hands together". When Narvin finally understood, she asked for another, but "down below", and tricked him by pulling her hand away at the last moment, exclaiming: "Too slow!" (AUDIO: Enemy Lines)
The initiator typically raised their hand, (AUDIO: The Thirteenth Stone, TV: Knock Knock) or held it out, (TV: Under the Lake) and often announced "high five!" in anticipation of the act. (AUDIO: Enemy Lines, TV: Dinosaurs on a Spaceship)
Though the Ninth, (TV: Boom Town) Tenth (TV: Time Crash) and Eleventh Doctors gladly initiated high fives when proud of themselves and their companions, (TV: The Hungry Earth, Hide) sometimes even using the gesture in place of words, (TV: Hide) the Fifth (TV: Time Crash) and Twelfth Doctors consistently refused to reciprocate the act, falling silent (TV: Knock Knock) or walking out of the room entirely to avoid it. (TV: Under the Lake)
When Ryan Sinclair gave Charlie Duffy a high five on a conveyor belt beneath the Kerb!am warehouse, for surviving so far, Charlie lost his balance and fell onto a lower conveyor belt. (TV: Kerblam!)
Queen Nefertiti, from 1334 BC, was not familiar with high fives, and did not know how to respond when Amy Pond offered up the gesture. (TV: Dinosaurs on a Spaceship)