A high school teacher and a young female student regularly met in secluded parks so they could engage in sexual activities, a court has been told.
The Brisbane District Court was on Monday told that Amanda Louise Thompson, 28, fell for a 14-year-old student who cannot be identified, when she was teaching at a high school south of Brisbane in April 2003.
The court was told Thompson, from Boronia Heights, initially took the teenager under her wing when she discovered the student had an eating disorder.
Prosecutor Todd Fuller said the pair became firm friends but that the relationship "spun out of control" over the next three years.
He said the pair quickly became inseparable and that they would regularly stay the night at each other's house.
The court was told they also took holidays together and that Thompson showered the student with gifts and notes.
Mr Fuller said the girl started lying to her parents so she could sneak out and meet up with Thompson.
He said they would organise regular trysts in local parks, where they would engage in oral sex and mutual masturbation.
The court was told that on a number of occasions Thompson would also penetrate the girl with everyday items such as a lollipop and a necklace.
Mr Fuller said the girl's parents became suspicious of their relationship and asked them repeatedly to keep the bedroom door open when Thompson stayed over.
He said Thompson's husband - who she later divorced - was also suspicious and that staff at the school had held a number of meetings to discuss the appropriateness of the teacher-student relationship.
The court was told Thompson repeatedly denied there was anything untoward about their friendship.
On Monday, she pleaded not guilty to one count of maintaining an unlawful relationship with a child between April 2003 and 2005.
The victim, who is now 19, will give evidence in a closed court.
The trial continues.