I recently got a Holosun IRIS 4 IR Laser. It comes with a two cable pressure pad. The straight plug sticks out over the rail on my hand guard near where I placed my thumb. I made this support for the crane plug to protect the port on the IRIS unit. 

I printed this model with PLA and the over hang was unsupported. There was a small amount of slack on the over hang. It can make a tighter fit on the rail or you can trim the slack with a utility knife for a loose fit. 

Install: Mount the laser where ever desired on the rail. Place the support a slot or two behind the unit and slide the plug in. The U shape and the rail lug will hold the support in place.