Marissa Sonkur, 22, was secretly filmed getting intimate behind a beer tent at packed Kelso Racecourse — about an hour outside of Edinburgh.
The sex tape, which shows the half-naked couple in the act, was later posted online.
Marissa, of Hawick, Roxburghshire, told pals: “It’s not the classiest thing I’ve ever done.”
The hairdresser was so mortified she hid from her mum for a week.
One of Marissa’s friends said: “Marissa ended up staying with a friend for a week because she couldn’t face her parents after it got out.
“It wasn’t just a one-time thing — she has been seeing the guy for a while.
“Everyone had a few drinks and then they left the tent together to get some privacy.
“But we think one of his pals followed them and recorded part of it without their knowledge.
“Everyone has seen it and her whole family know about the video, even her gran.
“She was totally gutted.
“She knows she was kind of in the wrong but this person should never have filmed it — it’s creepy.”