A difficult-to-quantify but quite vocal group of people can’t fathom how a woman could willingly go home with a man and then not engage in consensual sex with that man.

It’s beyond the bounds of logic, to them, that a woman could flirt with a man and not intend for that to lead immediately, that night, to sex.

Women, they argue, should understand this expectation and behave accordingly.

Don’t ask for it, in other words, if you don’t want it.

I bring this up not to speculate on the guilt or innocence of any one person, but to focus the conversation briefly on one fact: Sex, particularly between people who don’t know each other very well, is an intricate web of cues, questions, expectations and desires — and the two people engaged in the lead-up are often spinning wildly different webs.

So.

If you’re navigating Tinder, heading to college or, say, scrolling through social media lately, consider that any number of things can happen between two interested, flirting people to make one person decide to stop short of sex.

And that is always and completely legit. Every time.

I can think of so many scenarios wherein a man and a woman meet, flirt and leave together, and then don’t engage in consensual sex. Here are a few possibilities:

» The woman is hoping to see the man again and has been told by every corner of society since the onset of adolescence that she shouldn’t have sex on the first date. "Why buy the cow when the milk is free," and all that. So she plans to go only so far until she sees if he calls or texts in the next day or two.

» Societal warnings about free milk aside, the woman thinks the man is fun and attractive, but isn’t sure if she’s that into him. She’ll decide once they’re away from the crowded, noisy bar.

» The man seemed nice enough earlier, but has turned sort of belligerent/surly/rude now that they’re alone.

» The man has terrible breath and really cheesy artwork on his walls and keeps calling her the wrong name.

» The woman is attracted to the man, decides she wants to have sex with him, and then has second thoughts before they get started: She’s not over her ex, this guy’s being kind of rough, she can’t shake the feeling that something’s not right.

» Neither of them has a condom.

Any and all of these scenarios can also apply, of course, to a man who decides he doesn’t want to have sex with a woman he flirted with earlier. Or a man and a man, a woman and a woman, etc.

The point is, consensual sex happens between two humans. At no point does one of those humans cease to matter as much as the other. At every point, beginning to end, both people need to be on board with where things are going.

Or one of them gets to shut it down. And the other one gets to honor that.

Every time.

This isn’t debatable. It’s not political correctness run amok, nor is it a tangle of mixed signals.

It’s a recognition of a single, inalterable truth: Your body belongs to you and you alone. It is never, at any point of an evening or courtship or full-on relationship, OK for someone else to decide what happens to it without your wholehearted consent.

Many people already understand this. Many more need to.

Heidi Stevens, Chicago Tribune