Why some men find sick pleasure in forcing women to watch them masturbate.

I was 23 when I was assaulted by a man on the street.

It was about 4pm on a Tuesday. Broad daylight. I was carrying home some groceries and talking to my sister about an overbearing personal trainer who kept calling her about a session even though she’d stopped going to the gym six months ago.

I saw a man walking towards us, slowly, non-threateningly. I think I nodded in acknowledgement.

But when he passed me, he lunged. He turned into an animal. There was a mad look in his eye as he grabbed under my shirt and pushed me off the view of the street into a driveway.

My sister yelled. I tried to push him away. And after maybe a minute, I felt him put his hand in his pocket, and was convinced he was going to pull out a knife.

“This man is going to really hurt me,” I remember thinking to myself.

But he didn’t pull out a knife. He began touching himself. As I lay on the ground, terrified, he pulled down his pants and masturbated – not far from my face.

He looked at me, and then over at my sister, his eyes betraying insanity.

By this point, my sister was on the phone to the police. It must have scared him, because he quickly pulled up his pants and ran in the same direction he came.

In this moment, the act of masturbation was one of violence. There was nothing even mildly sexual about it. It wasn’t about desire or attraction. It was about power.

Television journalist Lauren Sivan alleges that one night, Harvey Weinstein attempted to kiss her at a restaurant, and she turned him down.

In response, she claims Weinstein told her to "stand there and shut up," before masturbating into a pot plant.

Such an allegation would be shocking if it weren't so common place. Model Angie Everhart alleges that while on a yacht, she awoke from a nap, to see Weinstein standing over her masturbating. There are multiple other women who have shared the same story.

The overwhelming question becomes why? 

What pleasure does one derive from making another human being feel desperately uncomfortable and violated?

Angelina Chapin interviewed sex therapist and clinical director of the Center for Healthy Sex in L.A., Alexandra Katehakis this week for The Cut, and asked what about this act appealed to predators.

"Exhibitionists purposefully look to shock their victims because they are angry," Katehakis says. "These are acts of revenge against women. These men are imposing the body part that is most threatening to a female and in doing so, they are acting out what is called 'sexualised hostility' against their prey.

"That look of fear or humiliation on women is arousing to them."

Listen: We discuss calling out the grope on Mamamia Out Loud. Post continues below.

Thus, the sense women have that men do this not because they want them but because they hate them, is legitimate.

Katehaskis says that much of this behaviour stems from their own childhood abuse - whether emotional or physical.

Their primary motive is to terrorise. They want their prey to beg them to stop. "There's a sadism and cruelty to it," Katehaskis says, "If she were to stand up to him or come after him, he [would likely] back down very quickly... he would lose all of his power."

With that said, women who encounter men masturbating at them have to process a level of shock. Their fight, flight or freeze instincts kick in and these aren't necessarily voluntary.

Chapin asks Katehaskis if she thinks men who force women to watch them masturbate without their consent are more likely to commit "more serious" sexual assault. "This behaviour is part of a spectrum," Katehaskis says, "I don't know that every guy who does this would go on to be a rapist... but they start violating their own values because they need more intensity and excitement."

Interestingly, she also says that these men become "addicted to the shame". They hate themselves afterwards.

To better understand the perpetrator's perspective, I found a site with thousands of contributors titled "My Masturbation".

The forum encourages (overwhelmingly) men to share their stories of masturbating in public.

"The best thing I know is to masturbate while there's lots of people around me," one man says. "Especially if it's mostly girls. Sometimes, after a party, we sleep in the same room, and I start jerking off, when I believe everyone's asleep. It's so fun knowing there's a girl less than a yard away, and you're masturbating..."

Another reads, "I love to bring myself to a climax in as public a place as possible, especially on a bus, train, or in an aircraft... I always have a large newspaper that I open and pretend to read." He proceeds to describe it as a 'turn on' to know there's women around, completely unaware of what he's doing.

Of course, I doubt the women are unaware. They're most likely intentionally looking away, their hearts speeding up and their hands beginning to shake, as they assess the level of threat.

Some men, it seems, think of it as a novelty - or a harmless sexual proclivity.

But for women, being masturbated at by a stranger can be highly traumatic. It is a tactic of intimidation, and an act that transmits shame onto the person forced to watch.

It exists on a continuum of sexual violence. In Katehaskis' words, "There is a sense of power, plus a hostile revenge."

Most men who masturbate in the presence of women, I'd speculate, know exactly what they're doing.

And it's to make women like you or I feel absolutely terrified.