There is no simple answer to this. But if there is pleasure derived the end of such a pleasure will be examined in the right context to determine its morality. But if there is no sexual pleasure derived then it is fine.
But generally speaking, insofar as the pleasure gained is not a deliberate move to forego the marital act, for instance culminating in masturbation or any other sexual action which is opposed to the ends of marriage then it might be an issue.
But these things are difficult to determine with one blanket response which is why you need to consult your priest to help you with a response proper to your specific situation. But it is important to read the following just to have an idea of the general teachings of the Church on Marital sexual morality.
“Lust is disordered desire for or inordinate enjoyment of sexual pleasure. Sexual pleasure is morally disordered when sought for itself, isolated from its procreative and unitive purposes.”
By masturbation is to be understood the deliberate stimulation of the genital organs in order to derive sexual pleasure. “Both the Magisterium of the Church, in the course of a constant tradition, and the moral sense of the faithful have been in no doubt and have firmly maintained that masturbation is an intrinsically and gravely disordered action.” “The deliberate use of the sexual faculty, for whatever reason, outside of marriage is essentially contrary to its purpose.” For here sexual pleasure is sought outside of “the sexual relationship which is demanded by the moral order and in which the total meaning of mutual self-giving and human procreation in the context of true love is achieved.”
To form an equitable judgment about the subjects’ moral responsibility and to guide pastoral action, one must take into account the affective immaturity, force of acquired habit, conditions of anxiety or other psychological or social factors that lessen, if not even reduce to a minimum, moral culpability. CCC 2351-52,
See also CCC 2360-65; Gen. 2:23-24; Matt. 19:1-12).
