I used sugru to add better grip to my Xbox360 controller. Normally these would cost you upward to $20.00 a pack, and their grip still isn't all that great. Some people even go as far as to replace the analog sticks with the ones from PlayStation controllers.With sugru, my grip has never been better. Definitely recommended over those other grip alternatives.
Step 1: Get some sugru.
Step 2: Follow the sugru usage instructions.
Don't want to mess it up now do we?
Step 3: MouldMould the sugru into your desired shape. I chose to go with a rounded surface, because it looks pretty and ads some nice functionality. If you want to mould it so that it has your thumb indent in it, first, wet your finger, now place it down on the sugru until you feel that your thumb has been moulded. Slowly remove your thumb from the sugru, and let it dry overnight. *Note: The reason you are adding water to the equation is because the sugru would just stick to your skin and ruin the whole process. The water acts as a lubricant .
Yay, you're done.