Q: Sometimes I cannot keep an erection long enough for my wife to climax. Is it a sin if I manually or orally complete her climax? Is it a sin if my wife manually or orally completes my climax? The older I get (I am 71) the more often this happens. I love my wife and could not see a day I would not like to try to make love to her.
Not every single sexual act, per se, need be procreative, but within a “sexual session,” if you will, there needs to be “openness” to procreative activity. In this case, you are in fact being open to procreation, but your age and your physical limitations prevent the pregnancy naturally. Normally, these acts would only be used as “foreplay” to pro-creative sexual activity ending with male ejaculation into the female. But in this case, that need not happen for obvious reasons.
So there can certainly be oral stimulation throughout sexual activity within any marriage. The larger question for most would be if one is using oral sex simply to avoid pregnancy, in order to achieve orgasms, then one is limiting their sexual union to merely give arousal rather than intimacy.
Enjoy the time you have with your wife and may God continue to bless your love for one another.
For more information on this refer to this article I wrote on BustedHalo some time ago.