The 35-year-old man, who cannot be named to protect the identity of the victim, will serve four months in custody after which he could be released on a good behaviour bond, subject to supervision, for eight months.

The offender appeared in Wagga District Court on Wednesday after pleading guilty to one count of using a carriage service to send indecent material to a person aged under 16 years.

Court documents state that about 1.22am on September 8, 2018, the offender 'waved' eight times to the victim on Facebook Messenger.

The victim and the offender were not friends on Facebook and the victim was not notified of having been contacted by the offender.

Five minutes after the initial contact, the offender sent the victim an explicit video.

Ten days later, the victim and her classmate saw the video on the victim's mobile phone.

In court, Judge Gordon Lerve said that no sentence other than jail would be appropriate.

He also said the impact statements from the two victims "speak eloquently of the type of harm that the type of insidious conduct in which this offender engaged can have on the victim".

"The effect of the crime on the victim is one of the factors that indicate that general deterrence is a real issue in sentencing for offences of this type," Judge Lerve said.

"While the actual transmission of the material may have been spontaneous, the offending involved the offender locating the offensive material and downloading and keeping it in order to be able to transmit that material.

"Plainly enough, the offender had put some thought into what he eventually did."

At the sentence hearing earlier this year, Commonwealth prosecutor Hannah Von Forell said the video was sent with a "sexually predatory purpose".

Ms Von Forell also said that general deterrence is a "highly relevant" factor because of the paramount public interest in promoting the protection of children and that there were two victims in the matter.

Defence lawyer Morgan Jones argued for a suspended jail sentence and said the offender has made, and is making, sincere attempts at rehabilitation.

However, Judge Lerve said he could not find good prospects of rehabilitation because of previous attempts and that "much will depend on how the offender engages with appropriate professionals in the future".

"Given the offender's record and the breaches of bonds ... taken with the fact that there have already been attempts at rehabilitation, I cannot find on balance that the offender is unlikely to re-offend," he said.

On Wednesday, the court also heard the offender has experienced illicit substance abuse and suffers from mental health issues.

While you're with us, did you know that you can now receive updates straight to you inbox each day at 6am from The Daily Advertiser? To make sure you're up to date with all the Wagga news sign up here.