There was only one other time, really. The instructor took half the students aside, told them something that the others couldn't hear, and then paired the in-the-know people with the others. Then some sort of two-person exercise began (can't remember now exactly what). On a certain cue from the instructor, the people who knew the secret tickled the others. Again, I think this was to create a sense of immediacy -- to be "in the moment," as they say in the theater.
Perhaps this instructor did have a thing for tickling!