Stand close towards the wall with the ball on your dominant hand and bounce it against the wall using only the tips of your fingers.
How many times you can do it without stopping?
Now, do the same with your non-dominant hand.
World Rugby has reportedly conceded Aaron Smith's disallowed try in the World Cup final should have stood.
"It is not only useful for staff who are experienced but a valuable tool for those subject staff who have to take teams."
The variety of sessions across sports - sometimes we steal session ideas from one sport and use them with another.