New got a couple of metres away from the woman, who told him to "put it away".
"The defendant quickly pulled his pants up and walked off," a police summary said.
Counsel Liam Collins said his client had little memory of his antics.
"He exposed his penis for a very brief period of time and put it away when the young person's asked him to," he said.
The reason New ended up in court was always down to his drinking, Collins said.
The defendant was last in trouble in mid-2018 when he was jailed for 10 months after sneaking into a student flat and helping himself to their alcohol.
A year earlier, he was locked up for nine months after he was spotted in a cemetery with his jeans around his ankles.
"This is the kind of behaviour that gives cause for concern," Judge David Robinson said.
While New turned up at court yesterday with a packed bag, prepared for a period of incarceration, the judge stepped back from that.
The defendant, he noted, was keen to participate in alcohol counselling and met the threshold to be assessed by a departmental psychologist.
New himself requested the court impose a no-alcohol clause on any sentence, to hold him to account.
Judge Robinson imposed 12 months' intensive supervision and 40 hours' community work.
He warned the defendant there were serious penalties for not adhering to the sentence he had imposed.