THE rules are changing. Once upon a time it was considered fine to flirt in the office, tell a woman she was "stunning", or catch the attention of a passing pedestrian with a wolf-whistle. Once upon a time you could get away with making a sexist quip like “while you’re down there ... ”, to a colleague who has bent over to pick something up – even if it did make her feel angry or humiliated. But if there’s one thing that we’ve learned from the Harvey Weinstein scandal and all the allegations and debate that have followed, it’s that whatever the older generation think, Millennials are redefining what sexual harassment is and how seriously we should take it.

The young are redefining how people should behave in public and work spaces, when dating and online, what flirting is, and what constitutes harassment. So is it possible, these days, to flirt, make sexual advances, function socially in the workplace without getting into difficulties or causing offence? Here, for the benefit of the perplexed, is a list of rules to help navigate the generally tricky waters of the post-Weinstein age.

1. Obtain consent. These days there’s never any question over whether no means no. It does.When looking to initiate any remotely sexual act, what you're looking for is not just the absence of a "no", but an enthusiastic "yes". The real issue is the need for affirmative consent, the kind that is clearly articulated, heartily given, and of the sort you don’t get when someone is out-cold intoxicated. Two years ago, the state of California, often a global leader in legal changes, signed into law affirmative consent legislation to make "yes means yes" the standard on college campuses. Some might feel all this verbal communication removes the mystery, but enthusiastic consent is key in a world that’s erasing some of the blurred lines.

2. Do a power check. Before making any kind of move, consider the power dynamics. If you’re in a position of authority, or significantly older than the person you’re attracted to, then you need to be doubly wary and almost triple-lock the consent agreement. Is the person really receptive to my advances? Is there any way in which they might be feeling their job may be on the line, or fearful of saying no because of risk to their career? This is one of the biggest shifts in terms of the way sexual harassment is perceived, and Millennial feminists have been key in pushing this into the mainstream.

3. Read the messages. Anyone who wants to make a sexual approach to another human being needs to become adept at reading body language and have a sophisticated grasp of the impact of what is being said even through texts or online messages. You can't get away with making a physical lunge and hoping that the other person doesn’t bat you back. The young aren’t necessarily any better at reading signals than the older generation – unless they are online, which is often where they are. In fact, research suggests that the young generation of digital natives, growing up with smartphones, are actually less skilled at reading facial signs and body language. However, since their route to both sex and friendship is increasingly via apps, the lack of that skill is not such a problem. Studies show Millennials and Generation Z (those under 24 years old) spend more time communicating with each other digitally than they do in person.

4. Don't give a xxxx. Today's young people have grown up greeting each other with hugs and kisses, and don’t have the same awkwardness over it as some of the older generation, who often learnt this more relaxed continental style of greeting later in life. However, particular types of embraces are likely to disappear, such as public lip-kissing between colleagues or strangers, and great big bear hugs that involve a casual grope. And, in emails and texts, we will probably see the slow but steady elimination of the xx sign-off, as it begins to look more and more like an inappropriate flirtation, unnecessary in an age when we have a wealth of emojis.

5. Don't touch. Groping, fondling, frottage, or any kind of non-consensual sexual touching were always against the rules. In fact they were illegal, considered sexual assault under the Sexual Offences Act (Scotland) 2009. What's changed is that people who who commit these acts are now more likely to be called out and reported. The Weinstein allegations and the #metoo campaign have led to increased awareness among women of what is inappropriate and what's illegal. Many of those who commit such assaults are still getting away with it, but plenty are being called out, reported or exposed.

6. Or whistle. Winking and wolf-whistling are not illegal. But there has been a profound generational shift in whether these two behaviours are considered acceptable. For instance a recent YouGov survey on sexual harassment in the public sphere found a strong correlation between a woman’s age and whether or not she considered wolf whistling to be sexual harassment, with two thirds (64 per cent) of 18-24 year old women saying it was, a figure that falls “with each subsequent age group to just 15 per cent among women aged 55 or over”. And while almost three quarters of the youngest age group considered it inappropriate (compared to around a fifth of over-55s), in 27 per cent of over-55s actually found it flattering. A similar pattern is found with winking: 28 per cent of 18-24 year old women said it was usually or always harassment, compared to 6 per cent of the over-55s.

7. Watch your language. The past few months of revelations have delivered plenty of examples from the movie industry of so-called compliments that now sound excruciating. Jennifer Lawrence recently revealed that she was once reassured by a director that she was “perfectly f**able”. But compliments also don’t have to have such explicit sexual content to push the boundaries of acceptability. A word like "gorgeous" or even “beautiful” could be problematic. For instance, the compliment that caused barrister Charlotte Proudman to hit out at lawyer Alex Carter-Silk for sexism, was the word “stunning”, posted in reaction to her LinkedIn profile picture. Proud was roundly trolled for exposing Silk, but nevertheless the debate left a lasting impact on the culture and many supported her.

Females, by the way, should be as wary as men. But compliments needn't be entirely out – it’s just that flirters have to get smarter, and apply their compliments to what a woman or man does, their ideas and work, rather than their physique. This applies not only to co-workers, but also to how you approach the young woman serving you at the bar, the air steward, the nurse, the receptionist, the shop assistant.

8. Locker room-style banter is out. Yes, Donald Trump managed to ride-out his appalling “p****-grabbing” comments of last year and plenty of banter stories still emerge from universities. But there’s a growing feeling that it’s just not tolerable. No man can assume he can get away without someone calling him out.

9. Socialise safely. Yes, you can still have a meeting in a bar or cafe with a member of the opposite sex. In fact, a man can view a meeting with a junior female colleague, conducted properly, as a positive act. Research has shown that when women miss out on such meetings they also miss out on the kind of mentoring and career connections that are helping their male colleagues to power. Just don’t compliment her on her appearance, wink, grope or get "handsy".

10. Flirt with care. Flirting has gone online – be wary of trying it in public. As one student activist told me, “Flirting? That’s what we do on Tinder.” Consequently, much of what might have been considered old-style flirting – chat-up routines or pick-up artist style approaches – are increasingly considered creepy and predatory by young women. Most likely you will get the cold shoulder. Better just get on Tinder and do it the modern way.

11. But don’t be creepy or sexist online. In the United States, according to a Pew study, about 25 percent of teens have had to unfriend or block a person on social media due to uncomfortable flirting tactics. Last year, Tinder and Grindr were linked to 500 crimes across England and Wales, among them sex attacks on children, but also harassment, malicious and abusive messages, illegal doxxing (publishing of personal information). An Australian report last year found that sexual harassment of women online risked becoming “an established norm in our digital society”.

There is however a fight-back. A shift is already happening, as women have tried to seize control of the online dating ground, by setting up feminist apps like Bumble, whose workforce is 80 per cent female and it has shown a zero-tolerance approach to sexist comments on the app. It was set up by Whitney Wolfe, a Tinder co-founder who left after a sexual harassment allegation and settlement. In the wake of the Weinstein allegations, she said: "I was being harassed daily.” She also observed of her new company: “We really have a zero tolerance policy for harassment in our platform or at our office. It's incredibly important that we all in our own respective fields and industries look in the mirror and say, 'What are we doing to be a part of the solution, not a part of the problem.'"

12. Workplace romances are on the wane. This isn’t to say they don't happen, or even that the proximity of working together isn’t still prompting a fair few affairs. However, the workplace is not, as it once was, the prime field of romance. It peaked in the 1990s and has been on the slide, in terms of percentage of couples who meet there, ever since. Now, however, according to research in the United States, online dating is starting to overtake all other methods, and work doesn’t even feature in the top three arenas for finding love: which are "through friends", "online" and "in bars and restaurants".

13. Be drink aware. Though it is now clearly established in law that a person is incapable of giving consent while intoxicated, still most casual and date sex is done after at least a drink or two. This means that the situation around alcohol is problematic and hotly debated. In The Daily Mail recently, criminal barrister Cathy McCulloch controversially advised that a man should not have sex with a woman even if she had had a single drink, lest he be accused of rape. “Young men must remember the two-stage test. First, if you are in doubt about whether she’s given consent, don’t have sex. Secondly, if you are not in doubt she’s consenting, ask yourself: has she had a drink? If yes, don’t have sex.”

However, alcohol is unlikely to be ditched from the dating cocktail. Both men and women drink in order to have sex: two thirds of Britons admitted in a survey last year that they had never been sober when they had had first-time sex with a new partner. And this hasn’t changed much among the Millennials. As Olivia Petter, contributor to the Independent’s Millennial Love podcast, said recently: “Modern dating culture is ... synonymous with drinking. I don’t think anyone I know, myself including, has gone on a date that hasn’t involved alcohol to some degree.”

What has changed, nevertheless, is attitudes towards drunk sex. There is condemnation of those who would take advantage of an intoxicated, barely conscious woman, rather than blame for the woman who does so, and fear of what extreme intoxication can lead to for both genders.

14. Treat other people as human beings rather than sexual objects. This is really another version of do onto others as you would have them do onto you. Sadly, for all we’ve moved on in recent years, it seems we are as far from creating this culture as ever. Lad culture still reigns on many university campuses. At school age, the key issue of consent isn’t taught nearly enough. Pornography is ubiquitous and many girls feel pressurised into acts inspired by it. Since the Rotherham sexual abuse scandal, we have seen a stream of grooming stories revolving around working-class, often vulnerable girls. Harassment is rife online. Girls appear to be viewed as sexual objects as much as at any time in recent history. Increasing numbers of men appear to be also. Until we embrace this one rule, and educate our children in how to live it out, we are a long way from creating a healthy sexual culture.