5 x 5 setting helps teams work on out-of-system setting and attacking. The ball should be set 5-feet from the sideline and 5-feet off the net and high (so hitters can take big approaches).
A coach starts the drill by bouncing a ball that the receiving team plays with a bump set to the 5 x 5 area. Then, an attacker takes a swing. With each successful attack, the team gets to rotate. But the set has to be in or near the 5 x 5 area, and the attack has to be aggressive.