Parents, let's talk about sex.

Without having to talk about sex.

Derek Johnson has figured out a way to do that with his three daughters, ages 15 through 20, and their teenage friends.

I reached out to the Plymouth dad after I noticed folks on Twitter giving him the virtual equivalent of a standing ovation in response to this tweet:

"After hearing a teenage girl say No to the same question 3 times, I looked at the boy & said, 'when a woman tells you no, you better listen' & gave a dad look. The wide eyes by the rest of the table meant it landed as I intended.

Teach about consent every chance you get."

The teens he had described in his tweet were his own 17-year-old daughter and her boyfriend. Derek explained to me he was sitting around the kitchen table with his daughters and their friends when the talk had turned to what they should do that evening.

"He loves Adam Sandler movies and really wanted her to watch 'Waterboy,' " Derek recalled. "She hates Adam Sandler. He just kept going, 'Let's just watch it, let's watch it, let's watch it.'

"After hearing her say 'no' three times in a row, I was like, 'Dude, listen. This is the signal you need to be listening for. She's being very clear. You need to listen.' "

And what exactly was that "dad look"?

Every kid will recognize this stone-cold stare: "I tilted my head down, but my eyes lifted up to look him straight in the eye. It was whisper-loud. It was a whisper to him, but loud so the whole table could hear it," Derek said. "There were a little theatrics around it."

The girls in the room instantly cheered, he recalled. The boys were like, "Omigod, what's going on?"

You may be thinking, "Hold up. This is some scared-straight drama all because of ... 'The Waterboy' "?

"It seems innocuous by itself, but this whole thing of not accepting no for an answer is troubling to me," Derek said. "If you're doing that in one part of your life, what's to say you're not going to do it in another part of your life?"

At 50, he doesn't recall having these conversations with his own parents growing up in the '70s and '80s. But while raising three girls, he says, there was no shortage of opportunities to teach the principles of consent.

Like when his oldest daughter, Emma, asked for his advice during her freshman year in high school after a recurring incident on the school bus. Every day, an intimidating boy would ask to sit next to her. He pursued her romantically, even prying her phone number from one of her friends when Emma refused to give it to him.

At 15, Emma said, she had a hard time telling him she didn't want to date him, but assumed she was sending him clear signals with her body language.

Her dad told her she needed to prioritize her safety and encouraged her to be straightforward with the boy — or remove herself from the situation. Eventually, she mustered the courage to tell him she wasn't interested in him, but then she stopped riding the bus entirely, she recalls.

"I was just so scared of this kid," Emma told me. "I wish I would have put myself on the bus and told this kid to [bug] off."

But let's face it — the onus should not be solely on girls to learn the importance of boundaries. Derek the Dad sometimes wonders: What are parents teaching their sons?

"We can't be in a society where we teach girls only to be defensive," he said. "Boys need to be taught to be not on the offense all the time."

My sons are still small, but I remember when my older boy was in kindergarten, he and his male classmates discovered that they could chase girls on the playground. Maybe it was benign fun, but one of my mom friends made me think when she asked her son, "Did the girls say it was OK?" She remembered being terrified when boys hounded her at recess.

Think of the times you've seen an adult tickle a kid even as the child is screaming, "Stop!" Or a grandmother who demands a kiss from her grandchild. These are all moments where we, as adults, can step in to make sure our kids know they can opt out.

Plant these seeds about consent early, so when hormones are raging and young people are beginning to think about sex, "at least there's some training in the back of their head that they can go back to," said Derek. Lessons about sexual consent won't feel so much of a stretch because they're already steeped in the concept.

Emma said she's lucky that both of her parents, who are now divorced, raised her and her sisters to respect boundaries and trust their emotions. And the fact that her dad is modeling this behavior means the world to her. "It makes me feel heard," said Emma, now a junior studying neuroscience at the University of Richmond in Virginia. (Her two sisters live with their mother in Virginia.)

We're squarely in what researchers call the "Red Zone," the first few months of the school year when sexual assaults on college campuses are more likely to peak. It generally lasts until Thanksgiving break, with assaults soaring in September and October.

If you are a man, how have you been protecting young women from sexual violence? What are you teaching your sons?

"Men — as role models, as adults — we need to be having this conversation with the boys that we're mentoring, coaching, teaching or raising as our own children," Derek said. "If the message is only coming from women, it doesn't feel like we're all in the same fight."

Be like Derek. Teach about consent every chance you get.