4 players start at the top of the channel working in pairs. On the whistle they drive a pair of contact shields back a few meters towards the side of the channel, then quickly run to reset and drive the other 2 contact shields back so both pairs are driving shields back simultaeously. After the second drive 2 players quickly tackle the bags and get up to support the other 2 who have run down the channel picking up the ball to attack the 2 defenders in a 2v4 situation.