Chronic masturbation can lead to desensitization of sexual sensation in the penis due to morphological or functional changes in nerve corpuscles.

“that is to say when there's stimulation for a long time then uh The receptors transiently can become less sensitive to touch and it's well known um particularly in males that uh that chronic masturbation can produce desensitization of sexual sensation in the penis and that could be as a result of a physical change a morphological change in the CR cor pusles um but it's more likely to be a change in their function that you wouldn't be able to Simply see by looking um at an outline of structure in the microscope”