The withdrawal of the penis, prior to ejaculation, either anal or vaginal.
This is where the penetrating partner, upon getting close to ejaculation, will remove the penis, and complete the act by ejaculating on the backside or belly of their partner, rather than within.
An ancient form of birth control, given that protective barriers were quite primitive at best, leaving little choice in the matter.
A study in 1991 claimed that some 38 million couples used this method of Birth Control (worldwide), and that it is today still popular, and is still a primary form of birth control for some couples who are adverse to either the loss of sensation from condoms, the effects of hormones by using the pill.
Modern era, shows that withdrawal was a popular means of birth control, though many claim it is less effective than condoms or other devices used by Women, such as an IUD or the Birth Control pills.
Primarily used as a birth control, studies show that it has a failure rate of only 4% when properly performed. However, that compares to a failure rate of 2% for proper use of condoms, failure rate of proper use of an IUD is 0.6% and 0.3% for the pill.
Note that means 'perfect use' which isn't all that easy. In those instances where it was not properly practiced, the failure rates for using condoms is at 10-18%, the Pill about 2-8%, the UID at about 9.8% and the withdrawal method about 18-28%.
Studies have also shown, that pre-cum generally does not have sperm, though it can if an earlier ejaculation occurred.
This method does not prevent the transmission of sexual diseases, or infections. Specifically, there has been studies, that have determined the presence of the HIV virus within pre seminal fluid (pre-cum) so that early withdrawal is not a safe way of avoiding possible infection.
Practice (Associated Acts): In condom sex, for pornographic depiction, the early withdrawal is simply removing the penis just prior to ejaculation, to photograph or video, the orgasm, and the ejaculation process by the models involved. (known as the money shot)
This form of 'withdrawal' is for cosmetic purposes, either in bareback sex, or condom sex. In some bareback pornography, the act of withdrawal is used as a prelude to further intercourse..
Noteworthy: While this method is not considered safe, when discussing risk of infection from STI's, STD's, HIV, it is safer than nothing.
Withdrawal limits the exchange of bodily fluids between partners, which does limit the risk of transmission, or the potency of such an infection.
It is still considered highly risky, if being used as a means of protection from infection.
To avoid the possibility of sperm being transmitted with pre cum, it is advised that a man who has already ejaculated, urinate prior to once more inserting their penis into their partner.
The urine will flush the sperm, as well as provide an acidic coating, that will kill the surviving sperm from the previous ejaculation.
While primarily used as a form of birth control, some have used it as a means of reducing infection or transmission of disease. This is not correct, as while the risk is reduced, it is not fully reduced.
In addition, some will still ejaculate, as the sensation associated with it, may not always be noticeable. Meaning that the moment for withdrawal passes, and semen actually is transferred between partners.