She’s a real pisser.

Accused Long Island Rail Road pension scammer Marie Rusin purposely peed in her pants in court Thursday to avoid dealing with the charges against her, a prosecutor said yesterday.

Former medical-office manager Rusin, 55, “slumped over and did other things to make it appear she needed medical attention,” Assistant US Attorney Justin Weddle said in Manhattan federal court, where stains from Rusin’s bladder bumble were still in evidence on a chair.

Weddle noted that after Rusin was taken to New York Downtown Hospital, she was released an hour or so later, saying, “She was fine and felt fine to return to court.”

Weddle added that last year, Rusin also “fabricated a medical condition” when she claimed she could not travel to Manhattan to meet prosecutors there.

Rusin’s lawyer, Robert DiDio, said Weddle was all wet.

“Nobody would go to such extreme lengths [and] . . . urinate all over herself,” he scoffed.

Rusin stayed dry for yesterday’s hearing and was freed on $750,000 bond.