The idea of having 2 players on each corner is that the second player is expected to put limited pressure on receiver making the situation more like a game environment. Once pressure is applied, players should drop in to an area where they can pass and receive with more time.Click this link for the actual drill - http://canyouplayfootball.com/kids-football-youth-football-training-drills-football-coaching.aspx?did=223
