http://cirp.org/pages/whycirc.html
"To obtain the best results one must cut away enough skin and mucous membrane to rather put it on the stretch when erections come later. There must be no play in the skin after the wound has thoroughly healed, but it must fit tightly over the penis, for should there be any play the patient will be found to readily resume his practice not begrudging the time and extra energy required to produce the orgasm… We may not be sure that we have done away with the possibility of masturbation, but we may feel confident that we have limited it to within the danger lines."
(E.J. Spratling, MD. Medical Record, Masturbation in the Adult, vol. 48, no. 13, September 28, 1895, pp. 442-443.)