For circumcised males, on whom the glans is mostly or completely uncovered, this technique creates more direct contact between the hand and the glans.
To avoid friction, irritation and soreness from this resulting friction, some may prefer to use a personal lubricant, masturbation cream or saliva.
Animal masturbation has been observed in many species, both in the wild and in captivity.
The English word masturbation was introduced in the 18th century, based on the Latin verb masturbari, alongside the more technical and slightly earlier onanism. Suggested derivations include an unattested word for penis, *mazdo, cognate with Greek mézea μέζεα, "genitals", or alternatively a corruption of an unattested *manusturpare ("to defile with the hand"), by association with turbare "to disturb".
Mutual masturbation (mutual manual stimulation of the genitals between partners) can be a substitute for sexual penetration.
Studies have found that masturbation is frequent in humans of both sexes and all ages, although there is variation.
The outer foreskin glides smoothly over the inner foreskin.The glans itself may widen and lengthen as the stimulation continues, becoming slightly darker in colour, while the gliding action of the foreskin reduces friction.