There is no question that completed oral sex or anal sex is the grave matter of mortal sin. It is the same sin committed by homosexuals who engage in those behaviors, and they thus deserve to be called forms of sodomy.
The issue of oral genital stimulation (OGS) as foreplay to the completed genital-genital marriage act is not the same issue as marital sodomy. Under some circumstances it can be good, even a form of charity. In other circumstances it can be a major distraction and harmful to a marriage.
Father Al Lauer, the late and great founder of Presentation Ministries strongly counsels against OGS for solely erotic purposes. “I have been asked to counsel over a hundred married couples about oral sex as foreplay. After some time of discernment, not one has maintained that oral sex was a true expression of love. The motivation behind oral sex is often lust. The spouse is not the focus of the sexual foreplay; rather, sexual stimulation is the focus. It could almost be said that one spouse is having sex with sex rather than with the other spouse. This focus on sex rather than on the spouse is a poison to love and marriage.” (See Oral Sex and Marriage, a brochure with an imprimatur published by Presentation Ministries and viewable at www.presentationministries.com/brochures/OralSex.asp.)
The problem is that excessive focus on ways to maximize the pleasure of the marriage act can distract both spouses from the reality that the marriage act ought to be a renewal of the faith and love and commitment of their original marriage covenant. What spouses really need is to help each other to grow in faith and holiness and to enjoy each other’s company in the kitchen and living room as well as in the bedroom.
On the other hand, if OGS is the only way that a wife can arouse her otherwise impotent husband sufficiently for their marriage act, it can be an act of marital love, even an act of charity.
Is there still some uncertainty? Father Lauer quotes Pope Pius XII as quoted in The Catechism of the Catholic Church, 2362. “The Creator Himself…established that in the [generative] function, spouses should experience pleasure and enjoyment of body and spirit. Therefore, the spouses do nothing evil in seeking this pleasure and enjoyment. They accept what the Creator has intended for them. At the same time, spouses should know how to keep themselves within the limits of just moderation.”
The question is, “What are the limits of just moderation?” The experience and wisdom of Father Lauer leads him to conclude that OGS is a huge distraction, at the least, and generally harmful to marriage. Whether it can be helpful in some marriages on some occasions is a question that is beyond my competence to answer. One certainty is that it must be completely mutual if practiced at all; that is, it may never be forced.
In summary: 1. OGS is lawful only between married spouses as foreplay to the completed genital-genital marriage act. 2. It may be very dangerous to the marriage relationship. 3. As couples age and impotence becomes a problem, it may be an act of charity. 4. It must be mutually acceptable.
John F. Kippley
Sex and the Marriage Covenant: A Basis for Morality (Ignatius)