The 20-year-old single mom Bristol Palin has revealed all the details of her affair with Levi Johnston, including how she lost her virginity, in her upcoming new book – “Not Afraid of Life: My Journey So Far”.

She said it wasn't a romantic experience as she lost her virginity while drunk during a camping trip.

Palin said that's the first time she drunk and when she woke up the next morning in her tent, she even couldn’t remember what happeded. She said Johnston was talking with his friends on the other side of the canvas.

Bristol Palin is the daughter of Sarah Palin. She is also the recent Dancing with the Stars contestant. She has a 2.5-year-old son called Tripp with Levi Johnston.

Bristol often blasts the cheating daddy of the baby in her memoir, saying the gnat named Levi Johnston constantly spreading false accusations against our family, and addressing Johnston as one who cheated on me about as frequently as he sharpened his hockey skates.

According to Bristol, Johnston promised that they would never have sex until they got married after the first tawdry night. Unfortunately they continue to do this. Bristol said she insisted on using birth control pills every time but it was useless.

After she was found pregnant, Johnston just said one sentence:”Better be a (bleeping) boy”.

It was said that Johnston refused to cut the cord at the hospital when Tripp was born in December. Soon the mother also discovered Johnston had been cheating on her and they broke up just then.

Dramatically they reunited again and claimed to engage 18 months later, which shocked their family. But the end of the story remained sad: Johnston had gotten another woman pregnant, which made Bristol finally gave up the beau.

The autobiography was published by William Morrow, co-written by author Nancy French and obtained by The Associated Press on Friday.

Meanwhile, Johnston plans to write his own book, Deer in the Headlights: My Life in Sarah Palin's Crosshairs, which will release this fall. He also claims to record his interactions with the Palins.

Maybe Johnston has something different to say about how Bristol Palin lost her virginity. Till then we need to wait.