When I was about 10, I wandered into my bedroom (well, the room on Exmoor I shared with bats) and a book had appeared on my bedside table.

Girls and Sex was the title of the slim paperback my mother had sourced for me during the summer holiday. My three brothers took turns with their own book, which was called, you guessed it, Boys and Sex.

Shortly afterwards, my father drove us back to prep school for the beginning of the autumn term. My older brother and I sat in our school uniforms (grey flannel shorts for him, navy pleated skirt for me) un-seatbelted on the bench seat in the back as we threaded through East Grinstead in the rain.

“Now, kids,” he said, as the windscreen wipers swished. “Has your mother talked to you yet about…” and then he went into a spasm of embarrassed throat clearing. “Yes!” we shrieked. “Don’t worry, Dada, it’s OK,” – though she hadn’t talked to us about masturbation at all, we just knew that was the topic he was under orders to raise.

“Oh fine,” he said, clearly relieved. “Nothing wrong with it, just don’t…” and trailed off. And that was it, apart from my grandparents’ issues of National Geographic in the bathroom, and my mother’s copy of Our Bodies Ourselves, which I would furtively examine when she was out, especially the grim obs and gynae chapter, which instructed women in the joys of examining their own cervixes with a speculum, accompanied by black-and-white photographs of the results.

When I say “that was it”, I mean that was my sex education. The most daring thing I witnessed on screen was Anna Friel’s lesbian kiss on Brookside and squirming when I made my father take us to see An Officer and a Gentleman starring Richard Gere. “Steamy grot!” he kept muttering during the (very tame) sex scenes. “Steamy grot!”

That was then; this is now.

The internet. Porn on smartphones. Sexting. PHSE classes in schools. Netflix. The younger generation literally has Sex Education on tap – and in widescreen.

In the fullness of my midlife, therefore, I feel I (if not my entire cohort) need educating all over again. This is why: I read widely; I have three grown-up children; I have been a journalist all my life; and every week I interview Difficult Women for my podcast. You’d think I would have managed to keep up at the back. But I’ve learnt it’s not enough to have read Delta of Venus as a teenager, married in my 20s, and had three babies in NHS teaching hospitals. We are in a whole new world in the 2020s.

I know this for many reasons, and one of them is that I broadcast on live radio. The other day I had to cast an eye over a list of offensive language for Ofcom. Reader, I didn’t know half these words existed, let alone being tempted to utter them on air! Bumberclaat. Choad. Bawbag. Put it this way, I’d definitely challenge if someone put these down on the Scrabble board. Yet, over Christmas, one of my millennial guests used all seven letters for “felching”, to a round of applause from the other players.

It’s not just me – even the unshockable experts in the field are struggling to keep up with the pace.

“There are practices that are being mainstreamed, normalised – and we could mention ‘pegging’ here – that many people haven’t heard of, let alone practised,” says Sophie Laybourne, a couples counsellor who specialises in sexual relationships.

But even the language is changing, too. We don’t or can’t say “erectile dysfunction” or “ED” any longer. We say “unreliable erections” as if the male member is prone to patchy mobile signal. We don’t say “sex addiction”, we now talk about “sexual compulsivity”. Everything around sex has been de-stigmatised. There is nothing deviant or perverted anymore…

As one friend my age who came to a turkey-soup lunch over the New Year put it, “This is what I can’t understand. Why don’t we talk about good old-fashioned sex maniacs anymore?”

The other sea-change has been around relationships. Custom is changing as well as practice.

A national newspaper editor in his 60s called me last week. “Forget adultery, that was so old hat, so 1990s. You should be writing a novel about polyamory.” He was on his carphone, so I wasn’t sure I’d heard him right. “Polly Amory?” I asked. “Is she a daughter of Ed and Alice Amory?”

He laughed and said no, polyamory – apparently it is all the rage in the US and is coming over here too, as is CNM. (This is not a cable network, dears. It’s “consensual non-monogamy”. I looked it up.)

Since I was single in my 20s, “throuples” have become a thing too – and all this leads me to this inescapable conclusion. The way we are having sex may be polymorphously perverse, but marriage hasn’t moved with the times, and that is causing some problems.

Matrimony binds most of us into monogamy, the system that the psychotherapist Esther Perel describes thus: “today we have to give one person what an entire village used to provide – financial and emotional support, companionship, entertainment, friendship, familiarity, mystery, love, sex, the works.”

No wonder that many find “the chains of wedlock so heavy that it takes two to bear them,” as Alexandre Dumas fils once mused, “sometimes three”.

And no wonder that apps offering alternatives are mushrooming on smartphones. Consider Feeld, an app designed to cater for those open to experiencing people and relationships in new ways. As the darkly alluring website puts it: “Polyamory, consensual non-monogamy, homo- and heteroflexibility, pansexuality, asexuality, aromanticism, voyeurism and kink are just a few of the sexual identities and desires that make up the Feeld community.”

There are at least 20 other classification options on Feeld, including GrayA for asexuals, and objectum sexual, for those who have sexual or romantic feelings toward inanimate objects. Before you titter, didn’t Tracey Emin marry a rock?

The days of “hatch, match and despatch” are behind us and we have to move with the times. As Sophie Laybourne says, “It’s all right for a woman to craft a penis and attach it surgically to her crotch, but the institution of marriage itself has not been re-evaluated – when is it going to wake up?”

Well, that is the question. One of many I expect we will be answering.

Welcome, then, to the new go-to column for all your sex and relationship queries. Let us go, you and I, into the thick of it without judgement. I’m absolutely here for this.

As a hardened hack and author of four novels (one of which won the Bad Sex prize), I’ve been around the block and feel on reasonably safe ground as a sounding board for most queries. My starting points are these: there is no such thing as a stupid or embarrassing question. If you want to ask something, chances are so do others. There are only embarrassing answers.

But for the more, er, granular and detailed questions on sex, I will be deploying Sophie, whose expertise and wisdom knows no bounds. With her holding our hands as resident sexpert in this brave new world, this will always be a safe space. And, in my view, an important, necessary and timely one.

All questions answered. Don’t be shy. After all, you can always say you’re asking for a friend.