A woman posed as a "muscular" dad-of-one to trick a single mum into having a sexual relationship with her, a court heard.
Kyran Lee, 25, who was formerly known as Fiona Manson, used a false internet identity to woo her victim.
She pretended to be a "tanned, muscular young man" called Joey G-Star Crislow and claimed to have a child.
Following contact through Facebook , text and phone calls, Lee ended up in bed with her victim.
Jonathan Straw, prosecuting, told a jury: "The victim was a single parent. Kyran Lee sent her presents including an engagement ring.
"When they met Kyran Lee wore a puffa jacket and a hat...They spent time together and shared a bed.
"The defendant wore a bodysuit and the lights were off. The offence took place three weeks after they met.
"The defendant gave the victim oral sex. Then with one hand on what she thought to be his [Lee's] penis he [Lee] penetrated her. He [Lee] used a sex toy ."
The jury heard the victim only discovered 'Joey's' true identity following a chance conversation.
Lee, of Gainsborough, Lincolnshire, admitted one charge of assault by penetration between 10 September 2012 and 15 October 2012.
Details of the offence emerged in a second case brought against Lee who was accused of sexually assaulting another woman.
A jury heard how she posed as a man called Daniel Blades to befriend a teenage single mother.
The young mum later complained that she had been sexually assaulted by Lee back in 2008.
Lee denied two charges and was cleared by a jury at Lincoln Crown Court following a seven day trial.
She admitted using a male identity but said that sex did not take place with the second woman.
Lee told the jury that she began to question her sexual identity from the age of 11.
She said: "I realised I wasn't happy. I didn't really know how to explain it to anybody.
"I just wanted to be a male. At the age of 15 or 16 I felt like I was a male."
Giving evidence during the trial Lee spoke about the victim she has admitted attacking.
She said: "I suppose I loved her. I spoke to her as someone else - Joey. I wanted to meet her as a man because I loved her.
"I didn't do anything sexual with her when I first met her. I didn't want to.
"It was only after she told me that the relationship couldn't continue unless I did have a sexual relationship with her.
"I loved her. She loved me. She wanted me to do things I didn't want to. She said the relationship couldn't carry on unless I did."
Lee was granted bail and is to be sentenced later this year for the assault by penetration charge.