Sex can be great, but if you're not being safe or you can't control your urges, it could be a sign of deeper mental health issues.
When Rachel was 18 she noticed her sex drive took a jump.
"It was literally all I could think about and if I wasn't having it then I would be doing something related to it, or watching it online," she told Hack.
"As I got a little bit older, it started getting to pretty much every day of the week and maybe two to three partners a week."
It wasn't long before it started taking a toll on her relationships and she decided she should look somewhere for help.
"I didn't like the person I was becoming because it was the total opposite of how my parents had raised me and that's when I knew I had to do something about it."
Rachel was putting away a bottle of spirits a night, and she started seeing a therapist for her drinking; there she also started talking about how much sex she was having.
She couldn't get it off her mind.
Her therapist suggested this was all self-destructive behaviour.
"He said it's very common in people who have bipolar disorder and Borderline Personality Disorder.
That's when I found out I had bipolar."
Not the only one
Liam, who's also 21, had a similar experience.
His sex drive was boosted by his Borderline Personality Disorder (BPD), which, like bipolar, is linked with self-destructive behaviour.
"When I was 15 the internet became a pretty easy way to express myself in a sexual way," he said.
"I was underage and the cohort of people who I was getting solicited by were generally older people who should not have been taking advantage of me."
Liam was having sex a few times a week, and had a "scorched earth policy", where he'd never sleep with the same partner twice.
He eventually realised these encounters weren't satisfying.
I probably wouldn't finish at all, then sometimes I would just get halfway through and I'd be like, 'Nup, I'm done'."
"When I wasn't enjoying it anymore ... I was still compelling myself to do stuff.
Even though he recognised he had an issue, it wasn't until he was hospitalised at 20 that he was diagnosed with BPD, correcting a previous bipolar diagnosis.
He now takes medication to try and manage the disorder. He said the meds had reduced his sex drive.
"My orgasms are not as potent or strong as they used to be, but at the same time I have been developing healthy modes of intimacy," he said.
"I'm not looking to self-destruct with another person. I'm seeking to be constructive."
What's going on here?
Changing sexual behaviour is a common symptom of psychiatric disorders, according to Professor Andrew Chanen, the deputy research director and head of personality disorder research at Orygen, the National Centre of Excellence in Mental Health and Substance Abuse.
"I would always ask a patient about their psychosexual development, their sexual history and about their current sexual behaviour."
But he said you shouldn't assume that more sex is bad.
What marks it as a symptom of a disorder is when it's uncharacteristic, or out of control, or unsafe."
Recently, Andrew has been researching how Borderline Personality Disorder affects the sex drive of young women.
"They have an earlier age of initiation of sexual behaviour, earlier age of sexual intercourse, they're more likely to have unsafe sex, they're more likely to be coerced into sex practices that they don't want to engage in," he said.
Andrew said this made a diagnosis for this disorder even more important, because there were clear sexual health implications.
Doing OK
Rachel has been getting regular therapy and taking medication.
"It's just magic that stuff, it's just helped me so much and I started being able to control my urges and I could actually do other things in the day and not just have sex on my mind 24/7," she told Hack.
Liam has to work a bit harder to keep himself in check.
"It's one of those things you just have to take week by week, or if not week by week, day by day, or hour by hour, or minute by minute, because it's always shifting," he said.
It's like being in quicksand, you never know if you're going to sucked in or if you're going to get out."