Danaher says:

Pins – static pinning and dynamic pinning: In Jiu jitsu the biggest point score come from pinning. Getting to mount or rear mount score double what a good takedown or sweep scores. You must be able to exhibit pinning skills in two main ways. The first is STATIC PINNING. This is the ability to hold a resisting opponent in place for time. The minimum requirement in three seconds, if you can’t hold the pin and exhibit control for three seconds you will not score. Of course in most cases you will want to hold much longer than this to tire and frustrate your opponent and set up further opportunities to score. The second is DYNAMIC PINNING. This involves transitions from one pin to another. This is without doubt the key to getting big scores in Jiu jitsu. If you can transition from pin to pin you will rack up big points and create the kind of movement that sets up submission. Nonetheless, it all starts with the foundation – static pins. You must learn to hold a man down and stick him. Here I am demonstrating one means of doing so – loading my weight to one side while posting wide with one hand and crossfacing with the other arm, whilst at the lower body cross ankles create a closed wedge around the hips. This creates a combination of wide base, preemptively loaded weight, closed wedges and head control that will make escape surprisingly difficult. Play around with these concepts along with experimenting with posture, particularly your spinal posture and you will soon be unmovable in top position!