It's just because their husbands love them, and want them to be perfect for Jesus!

On a pain scale of one to 10, Chelsea ranks the epidural-free birth of her child as a six. Her husband’s spankings? Those are an eight.

First, he uses his hands for “warm-up” slaps. Then comes a combination of tools based on the specific infraction. The wooden spoon is the least severe; for the worst rule-breaking—like texting while driving (“It could kill me,” Chelsea admits) or moving money between accounts without his permission—she’ll be hit with something else: a hairbrush, a paddle, or a leather strap.

But this isn’t domestic abuse, Chelsea says. This is for Jesus.

Chelsea and her husband Clint, who asked that I use only their first names, belong to a small subculture of religious couples who practice “Christian Domestic Discipline,” a lifestyle that calls for a wife to be completely submissive to her husband. Referred to as CDD by its followers, the practice often includes spanking and other types corporal punishments administered by husbands—and ostensibly ordained by God.

While the private nature of the discipline makes it difficult to estimate the number of adherents, activity in several online forums suggests a figure in the low thousands. Devotees call CDD an alternative lifestyle and enthusiastically sing its praises; for critics, it’s nothing but domestic abuse by another name.

Clint was in the room while I talked to Chelsea. They do everything together, including running their blog, Learning DD, which chronicles their exploration of domestic discipline. When Chelsea gets flummoxed by a question, she asks Clint for guidance in a voice so high-pitched that it belies her 28 years: “Honey, how long does the spanking usually last?” (About 5 minutes, Clint says.)

He has left bruises, Chelsea says, but it’s rare, and she attributes them to anemia.

You don’t have to be a Christian to practice domestic discipline, although many of its practitioners say they believe that domestic discipline goes hand in hand with their faith. Specifics of the practice vary by couple, though CDDers all seem to follow a few basic principles. Foremost, that the Bible commands a husband to be the head of the household, and the wife must submit to him, in every way, or face painful chastisement.

When a wife breaks her husband’s rules—rolling her eyes, maybe, or just feeling “meh,” as one blogger put it—that can equal punishments which are often corporal but can also be “corner time”; writing lines (think “I will not disobey my master” 1,000 times); losing a privilege like internet access; or being “humbled” by some sort of nude humiliation. Some practice “maintenance spanking,” wherein good girls are slapped on a schedule to remind them who’s boss; some don’t. Some couples keep the lifestyle from their children; others, like CDD blogger Stormy, don’t. “Not only does he spank me with no questions asked for disrespect or attitude in front of them, but I am also required to make an apology to each of them,” she writes.