My husband and I practice NFP but there are times where we throw in the towel and embrace the possibility of another child during possible fertility. Lately, (as modestly as I can put it) we will come together and my husband is unable to complete the act. Things die down but try as we might, we cannot complete the act to either (or his) finish. It is not consistent - sometimes it is completed. We do not have the intention of coitus interruptus but it is very hard to get things going again when he is slow to orgasm and it does get tiring. And we are not talking about a few minutes....we do try for an hour or more. Sometimes we have to give up trying to complete the act.
"It is the test of a good religion whether you can joke about it." ~ G.K. Chesterton
In love with my faith, the Doctor and Spock. Raising a herd of fellow Catholic nerdlings.