Understanding consent for sex can be tricky. Here’s a cute cartoon that explains it.

In a classroom, teaching consent for sexual situations is often met with a lot of questioning raised hands: Doesn’t interrupting every stage of a hookup kill the mood? How do you even bring it up? Isn’t that awkward?

New York Times reporter Jessica Medina experienced it firsthand last year while visiting the Urban School, a private high school in San Francisco, during a class on sexual assault:

Consent from the person you are kissing — or more — is not merely silence or a lack of protest, Shafia Zaloom, a health educator at the Urban School of San Francisco, told the students. They listened raptly, but several did not disguise how puzzled they felt.

“What does that mean — you have to say ‘yes’ every 10 minutes?” asked Aidan Ryan, 16, who sat near the front of the room.

“Pretty much,” Ms. Zaloom answered. “It’s not a timing thing, but whoever initiates things to another level has to ask.”

This confusion is nothing new. That’s why last year the Thames Valley police station in England shared a video to try to explain consent in the most British way possible: comparing asking for consent to serving tea to a friend.

Because “whether it is tea or sex, consent is everything,” the viral video’s narrator said.

“Maybe they were conscious when you asked them if they wanted tea, and they said ‘yes.’ But in the time it took you to boil the kettle, brew the tea, and add the milk they are now unconscious. Don’t make them drink the tea. They said ‘yes’ then, sure, but unconscious people don’t want tea.”

The video has been translated into French and Spanish, and re-narrated in English with an American accent.

Serving tea seems simple enough, but the idea of consent continues to puzzle people even when the stakes are as high as sexual assault or rape. Take Brock Turner, the 20-year-old former Stanford student sentenced to six months of jail time for sexually assaulting an unconscious woman. He defended his actions by citing both the prevalence of alcohol and the assumption of mutual interest.

And laws around consent are changing. Two years ago, California became the first state to mandate a “yes means yes” rule, meaning that sexual consent is defined by the presence of a “yes,” not the absence of a “no”: If both people do not affirmatively consent to a sexual act, it can be considered assault. Since then, affirmative consent has been mandated on college campuses across the country, including in Michigan and New York.

What might be seen as a commonsense understanding of consent has struck ire from some, like Libertarian writer Robert Carle, who argue affirmative consent makes “normal human interaction” into sexual offense, and author Judith Shulevitz, who argued this approach would make sex more anxiety-producing.

Changing the societal understanding of consent has, understandably, proved to be a big challenge. Universities across the country increasingly include consent as part of freshman orientation. At an educational event at Trinity College in Connecticut, the New York Times reported on an event with Jonathan Kalin, the founder of the education group Party With Consent:

“In my experience, when you ask men on college campuses where they learned about consent, they sort of look at you blankly and say, ‘What do you mean?’” Kalin told a reporter. It makes his service particularly necessary, the Times reported:

Most rape is not the result of a misunderstanding. To the contrary, one-fourth to two-thirds of rapists are serial attackers, studies show. And yet how we understand consent has been at the core of a number of recent rape cases, and it is a focus of a growing field of study. When it comes to young people today, and college, and hooking up, and drinking, and rape culture, and consent, there’s enough confusion that the services of people like Mr. Kalin are in high demand.