This action results in no direct stimulation of the head of the penis and ejaculation is achieved almost entirely from stimulation of the penis shaft and its contact against the underside of the head of the penis only.
The most common form of masturbation, especially in circumcised males, is to wrap one or both hands or several fingers and thumb around the erect penis and stroke it up and down until ejaculation.
It collects semen before, during, and after ejaculation, keeping semen from entering the uterus through the cervix and thus protecting against pregnancy.
Another common method is to rub the erect penis against a smooth surface, such as a mattress or pillow until ejaculation is reached.
It collects semen before, during, and after ejaculation, keeping semen from entering the uterus, thus protecting against pregnancy.