Provided that by “oral sex” you mean “foreplay” and that by “regular sexual intercourse” you mean, sexual intercourse which does not violate the two fold ends of the conjugal act then yes it is.
What are the two fold ends of the conjugal act?
The Catechism of the Catholic Church states in 1601 “…[Marriage] by its nature [is] ordered toward the good of the spouses and the procreation and education of offspring. …”
As long as the two-fold purpose of marriage is not subverted - such as when Onan “…spilled the semen on the ground (Gen 38:9)”, clearly violating the second purpose stated above, there is nothing immoral with oral sex within marriage.
Matt Fradd
