Teah Vincent invited the boy upstairs to his bedroom, then undressed before laying him on his bed and riding him up, Gloucester Crown Court told.
Ms Vincent, from Gloucestershire, admits to having sex with the boy in 2018, but says she thought he was over 16 at the time.
Prosecutor Christopher Smyth told the jury that the two boys spent the afternoon playing football in a park at a nearby park.
At around 5 p.m., Ms. Vincent, a nearby resident, offered them a glass of water at her home, he said.
“The boys accepted Ms. Vincent’s offer and returned home. One of the boys knew Vincent but the alleged victim had not.
“They sat down at the kitchen table.
“Ms. Vincent said she thought she knew one of them and told him she understood he had a child on the way. He told her he was only 14 and was still in school. ”
“The three of them talked about school life for a while before the topic was changed to Vincent speaking about his body.
“She said she covered herself up quickly and dressed as fast as she could.
“She then moved the conversation to talk about sex. The slightly older boy felt like Madame Vincent was coming on the younger one but he felt the situation was lost on him.
“Then she invited the youngest boy upstairs. He went upstairs thinking there would be a television or some other gaming device while his friend stayed downstairs in the kitchen.
“Ms. Vincent then took the boy to his room and told him to sit on the bed. She left the room and reappeared moments later after removing her clothes.
“The boy had a strong feeling that the situation was not right.
“He knew he was underage and there was a big age gap between them – she was more than double his age.
“In the end, he pushed her away, got dressed and ran downstairs. The alleged victim’s friend said he heard sexual noises on the stairs.
“He felt uncomfortable and left the house for a short while before coming back. He said he felt like his friend had been an idiot.
“Another mutual friend of the boys, a girl, said the victim had been an ‘absolute idiot’ and advised him to tell his parents.
“Three days later, the girl, along with two others, went to see the victim and her mother. They told him what had happened.
“The mother then went to see Vincent at his home.
“When Ms. Vincent opened the door, the mother said, ‘What the hell do I hear you’re having sex with a 14 year old? It’s my son.
“Ms. Vincent said, ‘Not now, I have my daughter with me’ and closed the door to the mother’s face.
“The victim said Vincent was insulting his mother. ”
The court heard that when Ms Vincent was arrested, she told a police officer that she thought the boy was much older.
Ms Vincent said that “the two young people told me they were 16”, but refused to answer any further questions.
The prosecutor explained to the jury that it was not in dispute that sexual intercourse had taken place, but that it was the youth’s age that was being questioned.
Catherine Flint, defending, said: “Ms Vincent had already spoken to the elder when he told her he was 18.
“After the couple entered the house,” she said, “the boy told her he was 16.
The jury heard the interview with the police of the alleged victim in which he said: “The woman told us that she was not sure of her body and that she covered herself quickly when she got out of the shower. .
“She invited me upstairs and I thought she had a game system or a TV. It was only me that she had invited. My friend stayed downstairs.
“She asked me to sit on the bed and left the room for a short while. When she returned, she was naked. She pulled my pants down and laid me down on the bed.
“She didn’t say anything until she sat on top of me with her legs straddled.
“It lasted about five minutes… I kicked the woman away from me. I got dressed and told my friend on the way down that we had to go.
“His reaction was that I had been an idiot.
“My mother went to see her a few days later and challenged her. She told him the police had to be involved. His response was, ‘Get the fucking police then.’
Vincent pleaded not guilty to having sex with the boy, knowing he was under 16 at the time.
The trial continues.