Get the Cubs to look at several of the behaviour codes, discuss the main points and come up with a new code
Copies or print outs of:
The firework code,
The internet safety code,
The countryside code - https://www.gov.uk/government/publications/the-countryside-code
The water safety code - http://www.rnss.co.uk/pdf/The Water Safety Code.pdf
Plain paper and pens
Give each Six the four codes, ask them to read and discuss among themselves (perhaps with an adult facilitator) then ask each Six to tell everyone about one of the codes, and the important points.
Then ask them to come up with their own code for how to keep safe.