He was involved in the family cleaning business, had a steady girlfriend, enjoyed a talent for soccer and was saving to buy his first house.

But inside, Suttle was a monster living a double life.

He preyed on vulnerable, underage girls via social media, grooming and manipulating his way into their lives so he could use them for his own insatiable sexual pleasure.

His victims, of which there are at least seven but likely more, were each drawn into Suttle's devious web in the same way: a friend request on Snapchat, followed by days, weeks or even sometimes months of exchanges that inevitably turned sexual when the 26-year-old sent them a picture of his erect penis.

He would then ask for intimate snaps of the girls in return, telling them he was a teenager himself.

Almost all of them rejected his initial requests, but Suttle's well rehearsed methodology - consisting of part charm, part master manipulation - eventually wore his victims down.

Some sent him naked pictures of themselves, others were coerced into going further.

Suttle eventually had sex with four of the seven victims, talking each of them into allowing him to film the acts on his mobile phone.

Read more: Illawarra Aldi basher sentenced after suffocating fellow inmate

(The intercourse was never forced, but each of the girls was unable to legally consent to the sex because they were underage).

He even paid one of the girls in cash, alcohol and cigarettes to send him naked pictures of herself and perform sex acts on him.

Suttle was arrested in February 2018 after one of the girls reported his depraved behaviour to her parents, then police.

He was charged and released on bail, however re-arrested two months later after breaching his bail by using social media. By this time, police had also discovered videos of the other victims on his phone.

He was charged with 86 offences in total, but admitted to 45 of them in a plea bargain struck with the Director of Public Prosecutions. He will formally be sentenced on 23 charges, with the remaining 22 to be taken into account to determine the objective seriousness at sentencing. The other 41 charges were withdrawn.

Included in the charges are four counts of using a child aged 14 to 18 for child prostitution. The charges carried a maximum jail term of 10 years.

Three of Suttle's victims provided statements to Wollongong District Court on Wednesday detailing the impact his actions had had on them.

"To this day I feel ashamed about myself," one of the teens wrote.

"I had never done anything sexual with a guy and the first time I was going to I wanted it to be special.

"He fed me with lies and manipulated me, he did stuff I didn't even expect he would do. He broke me as a person."

The second girl told the court she still carried an "insidious" feeling with her on a daily basis.

"I remember the way my body hurt during and after our encounters," she said.

"I remember the overwhelming feeling of guilt, confusion and self-loathing, and just not being able to fully comprehend what was going on.

"Looking back, I was too young to understand what I was doing, I was young and naiive and you knew that - you took advantage of that."

The third teen revealed she had been scared when her parents found out what had happened.

"The first they knew about it was from the police. I felt I had let them down," she said.

"I thought they might look at me differently but I now know they don't."

A psychologist brought in to review Suttle ahead of his sentencing diagnosed him with a sex addiction, a daily gambling habit and severe depression, all of which coincided with a back injury in 2015 that left him bed-ridden and unable to play soccer for almost a year.

"Mr Suttle reported experiencing profound depression following his operation in 2015," psychologist Anita Duffy wrote.

"He was in bed, in pain and could not envisage returning to his job or playing soccer. He began to get involved in social media and this marked the rise of online gambling and sexual contact via the internet."

Ms Duffy said Suttle used both sex and gambling to escape his low mood and boredom and admitted hiding his sexual encounters and online persona from his then-girlfriend.

"He regarded his sexual behaviour as an addiction," she said.

"He was often up until 2am sending messages and photos. He tried to stop this behaviour but was unable to do so until his arrest and imprisonment.

"His sex addiction extended beyond the internet and he had sexual encounters with many females - he had "no filter" and was indiscriminate in his choice of sex partners.

"He estimated that 20 per cent of his partners were underage...he justified to himself that they knew what they were doing.

Ms Duffy concluded that Suttle would benefit from sex offender programs while in custody and individual counselling sessions once released.

Suttle's lawyers tendered a handwritten letter of apology as part of their case on sentencing, saying their client's remorse was there in black and white.

"Looking back on my crimes and poor choices I am deeply ashamed and disappointed in myself for my disgusting behaviour towards these young girls," Suttle wrote.

"Being incarcerated has been very tough...it's been a hard lesson but a lesson I deserve.

"I'm determined to become a better person, completing all courses and continue working with my psychologist...to help my sex and gambling addiction.

"I will work towards earning the trust back I once had with my family, friends and the wider community."

Suttle remains behind bars and will be sentenced on October 3.