A man who was facing child porn and grooming charges when he sexually assaulted a bullied teenager in a cinema toilet will remain behind bars until at least 2021.
An Nguyen, 27, was on bail over a large cache of child porn and for grooming an 11-year-old, when he convinced a 13-year-old boy he added on Facebook to meet him at a Bankstown cinema in January 2015.
A Downing Centre District Court has heard the man forced his tongue into the boy's mouth behind a building before convincing the reluctant child to go to the toilet area of the cinemas.
Nguyen pulled the child into a cubicle and locked the door, before performing oral sex on him, the court heard.
"The offender attempted to kiss the complainant again (after the assault)," Judge Helen Syme said during sentencing on Friday.
Judge Syme said Nguyen told the child online he would protect him and offered bribes to encourage a meeting.
The man, who used a different name to send a Facebook friend request, also continuously asked the child to send him pictures.
"As a result of the persistence of Mr Nguyen, the child sent several photographs of himself," Judge Syme said.
"Including photos focusing on his genitals."
Nguyen pleaded guilty to numerous offences including aggravated sexual intercourse without consent of a person under 16 years.
He also pleaded guilty to earlier offences, for which he was on bail when he lured the child to the cinema.
The court heard Nintendo Australia had previously tipped off police about Nguyen in 2014, after he started telling an 11-year-old online that they should be lovers and engage in kissing and hugging.
Police investigating the matter searched Nguyen's computer and USB, finding more than than 8600 child porn images and videos, the court heard.
Judge Syme said Nguyen, who migrated from Vietnam in 2009, had previously minimised his offending and seemed to have a limited insight into his "callous and predatory" crimes.
But she said the socially isolated man was willing to take part in therapy and his chances of rehabilitation would be greatly improved if he went through sex offender programs in custody.
Nguyen's mother became hysterical as the judge handed her son a maximum sentence of nine years and one month in jail.
He was given a backdated non-parole period of six years and four months, meaning he will be eligible for release in June 2021.
