Each customer has a proper thumb lateral pitch based on the thumb hinge. Determining that is part of the fitting process. Usually it is between 1/4 left and 1/4 right. That applies both to right and left handers, from here on I'm talking about right handers when discussing pitch directions. Reverse for left handers.
The proper lateral pitch will give a clean release without causing blisters, callouses, etc., assuming the customer does not "knuckle" his thumb and the forward/reverse pitch is also correct.
Moving the pitch in either lateral direction can cause blisters and/or callouses. Moving the pitch to the right (from the proper pitch) will promote turning the ball when releasing. In fact, if you move the pitch far enough right the customer will be forced to rotate the ball to get out of the thumb cleanly. Serious blistering or callousing can result.
Moving the pitch to the left (from the proper pitch) makes it easier to release the thumb without rotating. Fewer problems with blistering or callousing occur unless the pitch is moved substantially left. It is best to fit a customer with the proper lateral pitch, but if I make a mistake I try to be sure it's to the left instead of to the right. -- JohnP
