OK then, let us look at a single point for you to play with and try in your dojo. Work it from the scenarios I suggest. Then I'll give you another one to experiment with. Experiment and report. Remember that by working a SINGLE point for practice, this is always in conjunction with otherwise good technique! The PP is not magic and will not work without technique.
You are in a standing grapple in close. You and uke are pushing and pulling each other back and forth trying to knock each other down while your hands are on each others shoulders and arms.
(1) Take your thumb over the inside mental foramen of uke's chin. Push it in and down to unlock his neck and make him turn his head. For reference, let us say you did this with your right hand to the right side of his chin.
(2) Then step in close on his right side. With your left hand, grab his belt rolling it over your fist so you can dig into UB 23 or GB 25.
(3) Sweep his right leg with your right leg calf to calf while pivoting toward your own left on your axis.
Uke should go down pretty easily. You shall have used the pressure points, primarily mental foramen, to destabilize uke's posture and stance. You can take him down hard or gently. Your choice! Try it.
Now here is your homework to experiment with for the same mental foramen point. http://www.gwc.maricopa.edu/class/bio201/skull/antskul.htm
On this diagram, the left foramen is clearly visible. Click on the hole and the answer should come up for you in the space. After you find it on the diagram, poke around on your own chin until you are sure you can feel the hole.
Uke has you mounted on the ground. You are face to face. You want to roll him off towards the side. His head is in close or medium close, but close enough for you to be able to reach his head points. Use mental foramen right hand to right side of chin or left to left while trapping the other arm or whatever you decide. Figure it out. How are you going to get him off you using this pressure point to assist you maneuver?