Advice from Christian sex manuals: Pray, read the Bible...and play with jump ropes and vibrators.
Levine says it's not just Christians who let fear of sex interfere with foreplay.
"Various religious groups, not just Christians but also Jews, Muslims, Hindus and Buddhists, have concerns about appropriate sexuality," Levine says. "Some of this is being driven by American culture, which produces pornographic magazines and steamy soap operas, and some of it is the appropriate concern religious groups have for the sanctity of the human body. It can actually be remarkably healthy."
She says Christian sex manuals are particularly healthy for evangelicals and Catholics, both of whom have long traditions of "denial of the flesh"--and accompanying embarrassment over sex.
Catholics are joining the movement with books such as "Tender Fires: The Spiritual Promise of Sexuality" by Fran Ferder and John Heagle, a nun-and-priest duo who run Therapy and Renewal Associates (TARA), a counseling center near Seattle.
"Catholic moral teaching pointed out sexual sin is illicit pleasure," Heagle says. "That suspicion of pleasure goes back to St. Augustine, who felt that all pleasure is disordered. We know now that pleasure is a built-in bodily response that is part of our physiological makeup."
Lynn Garrett, religion editor at Publishers Weekly, says the LaHaye book (yes, the same Tim LaHaye who authors the wildly popular "Left Behind" series) was a groundbreaking volume that has sold millions since it was published in 1976.
"Christian publishers do a tremendous number of books on marriage, family, parenting and relationships," she says. "In some of those books, sex is a part of it. For a lot of Christian publishers, that's the preferred way of doing [sex] because their philosophy is that sex is a part of marriage."
Despite their popularity, she doesn't envision a flood of new Christian sex manuals.
"The market may be growing, but that doesn't mean there will be more titles," she says. "There just may be more discussion of it than there was in the past."