I recommend using tape on the "SIDE" of your thumb hole. Here's why-it doesn't change your span, it doesn't cause a blister on the back of your thumb, and it allows the ball to have room to "vent". I haven't ripped a blister in many, many years, and I have bowled in 16 game marathons. I use 1" johnson & johnson waterproof tape. Now I have been doing this for about 20 years and have to admit trying everything from electrical tape(GREAT unless you have to remove it and get the adhesive off the piece right under it), to the tape you use on your thumb. It doesn't cost much, and is worth a try. I hope this helps. the don