This is a long form structure where a group song advances the arc of the story using any manner of improvised group song. In this case Doo Wop
The host has the performers line up facing the audience. They get in synch with some collective repetitive action like finger snapping. Once in synch the performers launch into song, telling a narrative in the pattern of A-A-B-B-B. This is an example with 3 performers, and ALL should include the audience.