Carlie Rose Attebury (PICTURES): Student Describes Sexual Relationship with Calif. Band Teacher

SANTA ANA, Calif. (CBS/KCAL/AP) A teenager testified Monday that he developed a crush on his high school band teacher at 15 years old that turned to kissing and then eventually a sexual relationship when he was 16.

PICTURES: Notorious Teacher Sex Scandals

The teen detailed his relationship with Carlie Rose Attebury, 31, on the first day of her sexual misconduct trial at an Orange County Superior Court. Attebury has denied having sex with the teen.

The teen said he met the teacher when he was a freshman in her marching band at El Modena High School in Orange, and developed feelings for her early in his sophomore year.

"I had ideas, but I didn't do anything about them," the teen testified, according to City News Service.

But he said he eventually kissed her in her office before the school's homecoming game in November 2007.

"I wasn't sure if it would progress forward, then it moved forward to a make-out," said the former student, now an 18-year-old freshman at Santa Ana College, according to City News Service.

Deputy District Attorney Katherine David said the relationship became sexual later that year, and she said in early 2008 Attebury moved near him to a house where they had sex frequently.

Prosecutors said the pair would at times openly hold hands, kiss and present themselves as a couple.

"This defendant treated this student as if they were in a boyfriend-girlfriend relationship," David said.

Parents from the band's booster club, some of whom were slated to testify later in the trial, noticed the pair's behavior and confronted Attebury about it.

Attebury has been charged with seven felonies including two counts of unlawful sexual intercourse with a minor younger than 16, and dissuading a witness from a crime.

The last charge stems from calls Attebury made to the boy after her arrest, in which she asked him to change his story, prosecutors allege.

Her attorney said during his opening statement that Attebury acknowledged she had sex with students and former students who were over 18 during sexual parties at her house, but denies that she had sex with the teen who testified.

In 2009, a former student who was in an alumni band pleaded guilty to felony extortion for threatening to reveal Attebury's relationship with the boy and demanding money and pornographic photos.

Miguel Lopez was sentenced to three years' probation in that case. His allegations led to Attebury's arrest.