Good defense is first based on good individual coverage, second on help. What I see when I watch you play is the expectation that help is there, so you don't have to work as hard to stay between your man and the basket. By extending the perimeter of the coverage, a pressure defense elongates the distance of recovery necessary for effective basket protection. You should not pressure as much if, in extending your defense, you allow the ball to crack the defensive perimeter with the pass or dribble. Pressure defense is about applying enough pressure to force the attacker or attacking team further from the basket to reduce their chances of scoring, and to increase the amount of time your help defenders have to position themselves to protect the basket.
Defensive Pressure is a little like walking a balance beam.
If you pressure too much, you lose your balance and the perimeter is penetrated. If you do not pressure enough, teams may pass the ball into dangerous scoring spots, to players who are more threats to score, or you allow a high percentage uncontested shot. When the ball cracks the perimeter or passes the defensive floor position of any individual, all defenders, except the one defending the ball, should automatically run to protect the basket . Part of being a successful player and defender is to understand that getting yourself into help position is a significant part of playing team pressure defense. This is important because when a teammate allows perimeter penetration, the pressure is eliminated and you have to re-establish an interior perimeter to protect the basket.