Sugru comes in basic colors you can mix.
Step 1: Play With It.
Roll it around in your palm to create the shades and shapes you like.
Step 2: Understand Problems, Conceive Solutions.
My Sennheiser earpod and microphone set has excellent sound but isn't custom fit to my outer ear canal. It's also very small, light and likely to fail eventually from being pulled in and out of my ears by the cables or wear out at the tiny, unreinforced plug end.
Step 3: Test Your Ideas and Adjust to Perfection.
Solve all these problems by molding Sugru around each stress point. Carefully avoid the inner earpiece and apply only to the outer housing where it joins to the cable. Surround the cable just a bit to provide flexible reinforcement and give you a little handle to pull them out with. Then insert the pod into the most comfortable position in your ear and press the Sugru into the outer canal only, filling perfectly the void between the pod and your external auditory meatus. This creates a snug fit that won't fall out, provides an extra layer of sound isolation and leaves you with a flat visible surface which looks like an expensive custom ear monitor.
Step 4: Design for Function, Durability and a Personalized Look.
Lastly, form an ergonomic bulge around the plug to reinforce the cable and provide an easy grip. Remember to avoid the last millimeter to achieve full tip insertion through a phone or iPad case. Test fit before allowing to cure.