David Russell Bond, 72, was jailed for 25 months in June last year, imposed for 20 indecent acts on seven children.
The ex-Otago Boys’ High School maths teacher was back before the Dunedin District Court yesterday after admitting three more counts of indecent assault against a 15-year-old in 1999.
Court documents said the charges represented at least 20 sex attacks over 10 months.
The victim said 24 years after the ordeal he remained "broken".
In a statement, the victim wrote about his initial pride at attending the school and acknowledged Bond’s reputation as a "great maths teacher".
The man said he was suffering significant family disruption at the time, a vulnerability he believed the defendant preyed upon.
The court heard he began skipping class before dropping out of school and turning to cannabis to deal with his shame and depression following the sexual assaults.
Bond, as he had done with others in his classes, would lean over the boy’s shoulder pretending to help him with his work.
While doing so, he would press his groin into the victim’s shoulder "maintaining this pressure while continuing to converse".
On one occasion, Bond instructed the victim to remain behind after class.
He closed the door and told the pupil to sit at a desk while he reviewed his work.
With the victim seated opposite him, Bond put his hand on the boy’s leg and moved it towards his groin.
"The victim became nauseous and confused by what was happening and ran from the classroom," a police summary said.
On another occasion, Bond orchestrated a similar scenario.
Once alone, the teacher pressed his groin into the victim’s left knee and locked his thigh between his legs.
Bond then began to "grind" himself against the boy’s knee.
The defendant has served two terms of home detention in the past decade for historic sex offences that emerged since his retirement, before he was jailed last year.
Judge Michael Turner highlighted the planning and premeditation it took for Bond to isolate his target from his classmates.
He called it "a huge breach of trust".
While serving his time in Rolleston Prison, Bond had completed a sex-offender programme and had reportedly gained some insight into the harm he had caused.
Judge Turner added four and a-half months to the current sentence, meaning the defendant’s release date would be pushed back to June.
