For the whole group. Player A goes to player B, player B speaks a few lines in character, player A responds to them matching player’s B character as much as possible. Now player A goes to player C, and player C starts the process again with a completely different character. Player A does this with every member of the group until everyone has had a turn.
If players are having trouble coming up with new characters, just tell them to mimic someone they know, or lead with a new part of their body.