How funny, "pull and PRAY"! I have never thought of the PRAY part.

At any rate, it is not a zero effectiveness method. I used it with my second H (now almost ex, formally/legally, and, ex since 2009, actually), interchangeably with condoms, so space our two daughters. When Julia was born, I got an IUD, because I did not plan more children.

He was opposed to the Pill because he believed that being on the Pill would affect my desire or harm me in some way. I did not argue - whatever.

So the girls were spaced exactly as we wanted, with each being an instant conception (conceived immediately when we wanted to conceive).

Sometimes he would use condoms and sometimes he would withdraw and finish on my breasts, tummy, or whatever. I trusted his skill since he was in his late 30s when we met, reported having been sexually active since age 13 usually using condoms, had previously married, etc. I would not have used this method with a young guy or with a non-husband or while on drugs that are teratogenic, because I would not have trusted the skill in the case of a young guy and would have been too concerned and also worried about diseases in the case of a non-husband. With a husband, with an understanding that if we were to conceive, we would have the child (I was not on any medications that could be teratogenic), it was an OK method, from time to time. Basically, it was an OK method because conception would not have been a catastrophe anyway, so it was Ok to be a little lax. And, it worked perfectly well.

Data-wise, quoting from Planned Parenthood:

How Effective Is Withdrawal?
Effectiveness is an important and common concern when choosing a birth control method. Like all birth control methods, the pull out method is much more effective when you do it correctly.

Of every 100 women whose partners use withdrawal, 4 will become pregnant each year if they always do it correctly.
Of every 100 women whose partners use withdrawal, 27 will become pregnant each year if they don't always do it correctly.
Couples who have great self-control, experience, and trust may use the pull out method more effectively. Men who use the pull out method must be able to know when they are reaching the point in sexual excitement when ejaculation can no longer be stopped or postponed. If you cannot predict this moment accurately, withdrawal will not be as effective.

Even if a man pulls out in time, pregnancy can still happen. Some experts believe that pre-ejaculate, or pre-cum, can pick up enough sperm left in the urethra from a previous ejaculation to cause pregnancy. If a man urinates between ejaculations before having sex again, it will help clear the urethra of sperm and may increase the effectiveness of withdrawal.

Pregnancy is also possible if semen or pre-ejaculate is spilled on the vulva.

Keep in mind that the withdrawal method does not protect you from sexually transmitted diseases. Use a latex condom or female condom to reduce the risk of infection.