The white players take it in turns to run at the two defenders in front of them and try to burst through their blockade.
The defenders cannot raise their arms to block the attacker's run but can use their arms to protect themselves and also use their entire body to try and make it difficult for the player to break through.
Start this drill at half pace.
Rotate the defending player's regularly to give everyone a chance to be both an attacker and a defender.
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.