A MOTHER of four who subjected her 11-year-old daughter to a "bizarre sex education" was jailed for four years yesterday.

The 37-year-old Sunshine Coast mother used her mobile phone to create three films showing her raping her youngest child and exposed her to other sexual activity "in response to repeated questions".

Judge John Robertson said the mother, through her "selfish criminal conduct", had deprived her daughter of the right to "a wholesome and loving relationship with her mother".

He said while sexual offences against children by their own mothers were "rare", the community acting through the courts should denounce "this shocking conduct" with a significant punishment.

Judge Robertson suspended the four-year jail term after the woman has served one year, leaving a three-year jail sentence hanging over her head and ordered her to do three years' probation.

Because the woman has already served 243 days in custody, she will be released in 122 days.

Maroochydore District Court heard how the woman started seeing the father of her four children when she was "virtually a child" at age 14 and had her first child at 16.

While she was still living at the family home on the Coast, she began a cyber-sex relationship with a man in Melbourne and became obsessed with sex.

They would send sexual videos to each other, which her daughter viewed, and the woman visited him three times.

"It is in this context the first of the bizarre and disturbing offences involving your daughter occurred," Judge Robertson said.

"Your conduct toward your daughter involved a very serious breach of trust.

"The relationship between mo-ther and child is seminal in our society.

"How she deals with it as she grows remains to be seen, but it is difficult to see how it could not result in long-term adverse consequences to her.

"You now admit what you have done was wrong.

"From the start you characterised your behaviour as some form of bizarre sex education with the child which did not involve sexual gratification from you.

"It appears you had a normal loving upbringing with parents andfamily who still support you.

"There is no psychological or intellectual reason to explain this shocking behaviour.

"Given this offending occurred in the context of this highly obsessive and sexual relationship with this man, defies logic and common sense to discount any level of sexual gratification in your behaviour."

Judge Robertson said the defence had asked him to note her "own dysfunctional attitude to matters sexual".

He said her husband was 12 years her senior and she had limited knowledge of appropriate sexual boundaries.

"You were obsessed with sex and your life was in chaos," he said.

"The psychologist report suggests the developing of some insight into your behaviour.

"Given the Department of Child Safety is now involved, I'm satisfied you are a low risk of reoffending."