The complainant. who cannot be named for legal reasons, said she had only had two or three drinks before accepting the gesture from the man, who she knew as 'Tyrese', but had no memory of leaving the club or arriving at his home.
Later, suspecting her drink may have been spiked, she exchanged text messages with the man, who told her they had 'slept together'.
The woman alleges it could not have been consensual because she did not know about it.
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A video of an evidential interview was played to jurors at Preston Crown Court in which she told officers she had met him in the club two weeks earlier and had slept with him consensually.
She said: " I remember thinking what have I done, he's older than me. I consented to it, that first time.
"I looked at his Facebook profile. I thought he looked quite old.
"He'd said his age was twenty something ."
The prosecution allege the man is Amos O'Cheng, 51, of Winckley Square, Preston.
He and his co-defendant Dickson Ngaunde, 37, of Stanford Avenue, Brighton, Sussex, are standing trial over alleged sexual exploitation crimes and sexual offences against women and girls in Preston.
O’Cheng denies three counts of raping a child, two of raping a woman, three of facilitating travel with a view to exploitation, false imprisonment, and four drugs charges, while Ngaunde is accused of raping a woman, false imprisonment and facilitating travel with a view to exploitation.
In the video the woman said she and her friend decided they were going to go out and arrived at Switch at about 11.30pm.
She added: "I remember drinking about half of the drink and then moving on to go to my friend.
"I can't remember anything past that point, I can't remember leaving. so then in the morning I remember waking up inside his apartment or house. I remember being woken up by my friend because she came into the room to wake me up
"I was completely naked in the bed - I can't tell you how.
" And then he drove us home back to my friend's house and we went into my friend's house and just slept because we were tired.
"It was just a weird feeling, I had never felt like that before
"The only way I can describe it is it was like I was there but not at the same time."
The court previously heard evidence about two other girls aged 14 and 16, who had been reported missing by their respective care homes and were feared to be at risk of sexual exploitation.
It is alleged the two girls had had sexual contact with a man called Black Max - who the prosecution also allege is O'Cheng - and that they were left distressed and frightened after being told he was HIV-positive.
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