Other version (Keep in mind, in the US, the term is "Soda", not "Pop"
Motions (for teacher use, only)
Present Simple:
Stage 1: Stand up and assume the pose of someone with an attitude problem.
Stage 2: Say in a bored, offhand way:
Have the students pronounce the "OK" in a very snooty manner.
(You may prefer to use "Add" instead of the word "Change":
Model how to play the game. (Starting from 1:05)
Note: One costume may not be suitable for all schools. There are many other versions that can be found online.