Posture comes first. Posture is the position of your body in relation to your opponent.
Pressure comes next. Pressure is most often, the motion your hips make from the posture.
Possibilities are what the combination of the two open up.
Jiu-Jitsu is the gentle art. But that doesn’t mean it is not uncomfortable for the person in the inferior position. What it means is that we constantly strive to do everything with the least amount of energy needed, this is efficiency, this is skillfulness, and this is ‘gentle’.