Critics question the competence of a celibate monk to write about sex
A Polish Catholic priest has published a book which provides married couples with a theological and practical guide to spicing up their sex lives.
In his book, Sex as you don't know it: for married couples who love God, Father Ksawery Knotz aims to sweep away the strait-laced attitudes many hold.
Sex in marriage, the Franciscan friar explains, should not be boring but "saucy, surprising and fantasy packed".
The book, which has the backing of the Polish Catholic Church, has been a hit.
The Sw. Pawel publishing house has ordered a reprint after Poles snapped up the first 5,000 copies within weeks of them going on sale.
In the book that has been dubbed the "Catholic Kama Sutra", Father Knotz goes into graphic detail about a subject many in the Church consider taboo.
"Some people, when they hear about the holiness of married sex, immediately imagine that such sex has to be deprived of joy, frivolous play, fantasy and attractive positions," he writes.
"[They think] it has to be sad like a traditional church hymn.
"Every act - a type of caress, a sexual position - with the goal of arousal is permitted and pleases God. During sexual intercourse, married couples can show their love in every way, can offer one another the most sought-after caresses."
Father Knotz believes sex is an important way for a husband and wife to express their love and grow closer to God.
"Married couples celebrate their sacrament, their life with Christ also during sex," he writes.
"Calling sex a celebration of the marriage sacrament raises its dignity in an exceptional way. Such a statement shocks people who learned to look at sexuality in a bad way. It is difficult for them to understand that God is also interested in their happy sex life and in this way gives them his gift."
But Father Knotz stresses the book does not differ from the Church's view on sex. He discourages the use of contraceptives, saying they "lead a married couple outside of Catholic culture and into a completely different lifestyle".
He also dismisses those that have questioned the competency of a celibate monk to write about sex, saying his experience comes from counselling married couples and from running a website giving sexual advice for almost a year.