Withdrawal is also called coitus interruptus or "pulling out" and it requires great self-control, experience, and trust, and as such, it is pretty unreliable. It works, some of the time, by taking the penis out of the vagina before you ejaculate, limiting the chances of any sperm reaching the egg. With each ejaculation you are releasing up to 400 Million sperms. However, not all sperm are released at climax, some are a little more eager than that and can survive inside a woman`s uterus for up to five days, so even though you don’t finish off, you could still finish up making her pregnant.