Jeff Todd, 51, of Ramsey Court, Lowood, pleaded guilty in the Warrnambool Magistrates Court this week to unlawful assault.

He was not convicted and fined $1000.

The court was told that on March 7 this year Todd was at the festival between 6.30pm and 7.30pm when he became involved in a verbal incident in a bar with a man not known to him.

Todd bumped into the man several times in a bar and was asked to move away before the victim requested security personnel to assist.

Todd moved away a few paces, made some derogatory comments, then came up behind the victim and grabbed his testicles with significant force.

"You've got no balls, mate," Todd told the victim and there was a short struggle before he released the victim's testicles.

Todd was kicked out of the venue and told not to come back.

He told police during an interview he had drunk a bottle of wine and had little recollection of the incident.

At the time Todd was suffering anxiety and depression and could have suffered a blackout.

The victim suffered pain for about 12 hours and Todd wrote a letter of apology which was passed on through police.

Defence counsel Danielle Svede said Todd had no prior convictions, glowing references and had not drunk alcohol since the incident.

She said the incident had a huge impact on her client's marriage, his wife was left shaken and Todd had consumed alcohol while on medication and with an empty stomach that night.

Ms Svede said her client was on 12 months leave from the air force, had undertaken anger management and knew his behaviour was inappropriate.

Magistrate Jonathan Klestadt said there should be no doubt in anyone's mind that the defendant's actions were appalling.

He said the folk festival was not a place to be confronted by drunken, boorish behaviour and assaulted.