Tasmania’s Supreme Court heard the 28-year-old woman – who cannot be named for legal reasons – pleaded guilty to five counts of having sex with a young person.
The teenager is the man’s son from a previous marriage and he has another young child with her. The couple have now split.
Crown Prosecutor Jackie Hartnett said the woman had gone to the teenager’s room in October 2012 last year to discuss his driving lessons.
“Although the pair had previously had a strained relationship, tickling led to kissing and then to intercourse,” The Tasmanian Mercury quotes her as saying.
The woman said she was “ashamed and embarrassed” by her conduct the New York Daily News reported.
She will be sentenced next week.
Not much is known about what kind of ghostly-going ons the man was expecting to capture when he set up his equipment.
She told The Huffington Post: "Maybe he used [the paranormal investigation] as an excuse because he thought something was up. Or maybe he thought it was really a ghost."