Prepare the input end of your NeoPixel strip by tinning the pads with solder. The strip won't work if you solder wires to the wrong end, so be sure the arrows on the PCB point away from the end you're wiring.
Solder three stranded wires, about eight inches long each, to the tinned pads of the NeoPixel strip. To help avoid the solder joints from being too cramped, solder the center pad's wire on the reverse side of the PCB (two on top, one on bottom), as shown.
Wrap three rare earth magnets in tape to prevent short circuits, and slide them into the NeoPixel strip sheathing, on the underside of the PCB. Our spike strip is 16 pixels long, and we used three magnets evenly spaced (one at each end and one in the center).
Prepare a protected work surface in an area with good ventilation.
Use Permatex 66B silicone adhesive to affix the 3D printed spikes to the NeoPixel strip. Apply both to the strip's silicone sheathing and the NinjaFlex strip of spikes, using a toothpick to spread it around if necessary.
Squish a bit of silicone adhesive into the ends of the NeoPixel strip sheathing to provide water resistance and strain relief.
Allow adhesive to dry overnight.