I've had this same problem for a lot of years and I just solved it a few months ago. I bought a roll of the Vise tape and cut it into pieces. I put a piece on the back of my thumb. The tape is flexible and sticks really well. I rub Easy Slide into the thumbhole after I clean the ball to help as well. If the thumb feels loose, I just add a piece of white tape for the front of my thumb and if it starts to get tight, I just take the tape out. It has really helped me to get a very clean release.