Men and women will go to great lengths to give themselves sexual satisfaction. Sometimes the results are not what was hoped for. One book mentions the case of a man who tried to masturbate by putting his penis into the sucking end of a vacuum-cleaner. The result was that all the skin was sucked off the penis. This method of masturbation "is not therefore recommended." P. Mantegazza has instanced the case of a penis caught in a bayonet tube and in the bath tub faucet. Many similar such cases are known to doctors and diligent researchers.