What I really want you to read and help me with will be red for your convenience.

Hello all. I have a Eurorack system with a PressurePoints mounted on.
PressurePoints is a device that has touchplates where pressure is applied and is converted to voltage.
In it's manual, it states that a specific power supply for Eurorack systems will cause problematic/odd behaviour on PressurePoints due to insufficient grounding. That's exactly the supply I have. Unfortunatelly I cannot change this for reasons that will be too much to explain.
But!!!!!
When I'm having my system connected to the FirefaceUC with at least one cable and I TOUCH the metallic thing that looks like a hook under the power plug of the Fireface(im sure it has a name im currently missing) and playing with PressurePoints, I get normal behaviour.

Is there anything I can do to free my other hand so to speak?
Ive seen somewhere that this 'metallic hook' under the power connection on the back of the Fireface is there for you to put some wire and connect the other end somewhere to ground the device, cant remember the exact words, cant find the source.

The abnormal behaviour of PressurePoints does NOT always happen though. There are a few arbitrary times where it behaves normal like I never had the wrong powersupply for it. Really odd cause I haven't yet sat down to collect data about the circumstances against whom it happens. I wish I got an answer that help me understand the whole situation with grounding, but solving the current issue is ofcourse a priority!

sorry if im being really noob here

Thank you for your time, I hope its something really simple like having a third arm.