In threes, the players stand in a row, the person in the middle faces player 1.
Player 1 then underhand passes the player in the middle, who return the ball back to player 1.
The player in the middle then spins around to receive the ball from player 2, whereby he returns it using the underhand pass.
In this exercise a player in the middle must be efficient in passing and able to position fastly.
Two balls thrown at the same time from the same side would increase the receiver's activity and make him/her assess the situation.
This would mean they would have to make a quick decision on which ball to pass first so there is still be time to dig the other ball.
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.