lopanreturns13 on Instructables writes:

Easy Steps for DYEING 1 Yard of Conductive Ribbon 4-Conductor:

1. Gather the Supplies
2. Fill a stainless steel pot with just enough water for 1 yd of ribbon to move freely (about 2 cups). Turn heat on high.
3. Add an 1/8 teaspoon of iDye Poly soluble dye packet and an 1/8 teaspoon of iDye Color Intensifier to water. Stir until dissolved.
4. Add pre-wetted ribbon and bring to a rolling boil. Maintain temperature and stir frequently for 10 minutes. For uniform color, use constant agitation with a wooden stirrer.
5. Rinse the ribbon in the sink until it washes clear.
6. Machine wash the ribbon in it’s own cycle with a mild detergent and dry.

Note: Utensils and Pot for Dyeing should NOT be used for Food

Conductive thread ribbon cable – White – 1 yard – This lightweight, flexible fabric ribbon cable contains four channels of conductive thread, perfect for wiring up wearables where flexibility is key. Use it to connect your conductive fabric gamepad to your microcontroller or computer!