Nathan John Palermo (38), a Dunedin sickness beneficiary, was in the manchester section at Farmers at 10.20am on September 1 when the urge overcame him.
He was seen by security staff pleasuring himself and later said he was struggling to control the impulse to commit such acts.
Judge John Macdonald told the Dunedin District Court this week that a psychiatrist's report on Palermo featured some "worrying aspects''.
The defendant made "frank admissions'' about his desire to commit more serious offences.
The judge said it appeared Palermo had seemingly committed other indecencies for which he had not been apprehended.
Among an extensive list of convictions was one previous for doing an indecent act in 2014 and a year later for making intimate visual recordings.
Palermo carried his phone around in a shopping basket which he positioned to film up women's skirts.
He told police he was "a dirty old pervert'', but denied his motives were sexual.
He was jailed for eight months for that offending.
Defence counsel Marie Taylor-Cyphers urged the court this week to deal with her client in a rehabilitative manner, saying that was the most pressing concern.
Judge Macdonald agreed.
He sentenced Palermo to 12 months' intensive supervision and four months' community detention.
The judge told the defendant he could not afford to be back in court on similar charges in the future because the outcome might be different.
"Do you understand what that means?''
"Yes I do, John,'' Palermo replied.
"I didn't realise we were on first-name terms,'' the judge said after the defendant had left the dock.
