It is part of traditional wisdom, and an important part, that we should not talk specifically or in detail about our personal sexual experiences.
Not talk about it ever.
Why? Because it is sacred, obviously.
OK, but why is it regarded as sacred?
Well, many reasons - but one neglected reason is that there are lots of bad things in life which will only be done (by most people) if and when people talk about them afterwards.
Most people are not content to sin in secret.
How many people would go bungee jumping if it was secret, and they could not tell anybody about it afterwards ever, nor show pictures and movies? How many people would get drunk? How many would have sexual affairs if they could not brag or weep about them with their pals?
A lot fewer than actually do these things now.
It is a great corruption of modernity, the way to which was paved by pop-Freudian psychology, that it is 'good to talk' about everything: and especially sex - 'unhealthy' to 'bottle anything up': and especially sex - and thereby people are led to do all kinds of sex-related things from the merely silly and wasteful, to the risky and show-offy, to the wicked and destructive... because (and only because) they are expecting to talk about them afterwards.
This is, or ought to be, common sense. It is hard to avoid noticing that the people who do the worst things most often - who are habitually wicked - are nearly always keen on telling everybody about it, get great satisfaction from telling everybody about it. The men boast to their mates, the women 'share' with their girlfriends.
When people talk specifically about their sexual experiences, by doing so they make them part of the world of entertainment, gossip, and sensational public experience.
Not only are the experiences instantly, then increasingly, devalued by the communication; the communication sets-up an expectation of having new kinds of experiences, novelties, variations - just like all the other things we talk about: news, books, TV, sports, summer holidays... these feed on change.
Since sexual experience is something which ought to be within permanent marriage, this is why sex should never be talked about.
Note - The above principle is true; and I am not interested in being told that there are marginal or grey areas and exceptions - such as some medical problems. There are always marginal/ grey areas and exceptions to any true moral principle (or scientific law) - and only inexperienced young children should be impressed by this fact.