Cosby's admission of drugging women was ruled admissible during Cosby's first trial as well, and this second jury has also heard Cosby's prior admissions of fondling Constand, although he maintains that their encounters were consensual.
Ms Jackson's testimony was blocked by a judge at last year's initial trial after Ms Constand denied knowing her.
Prosecutors have suggested he gave her something stronger - perhaps quaaludes, a popular party drug in the 1970s that was banned in the U.S. in 1982.
She testified that she had gotten to know Cosby when she was operations manager for Temple University's womens' basketball team. They argued to the court, the statements are irrelevant because there is no evidence Cosby gave Constand the now-banned drug.
Prosecutors are building to the conclusion of their case against comedian Bill Cosby in his sexual assault retrial.
She said she accepted pills from Bill to help her "relax" and woke up to him spooning her and assaulting her.
As Cosby arrived at the suburban Philadelphia courthouse Tuesday, spokeswoman Ebonee Benson told reporters that their testimony "seemed to be more colorful and more embellished" than at the first trial.
"He said to me, 'Don't worry, Mom, there was no penile penetration, ' " Gianna Constand shared with the court.
"Did you ever fabricate a scheme to falsely accuse him for money?" Cosby lawyer Tom Mesereau previously had asked her about the Valentine's Day calls and mentioned them in his opening statement. He's been accused of assaulting somewhere around 60 women.More news: Jeff Bezos says Amazon Prime now has over 100 million members
She reached a $3.38 million private settlement with Cosby in 2006 after several Jane Doe witnesses lined up to testify about their own, allegedly similar assaults. "I wanted a paycheque", she said. "This isn't about money".
Constand, who stepped down from the stand Monday, says that though Cosby "came on" to her before the alleged assault - putting his hand on her thigh and once trying to unbutton her trousers - she stopped him and they never shared any consensual sexual contact.
Andrea Constand's testimony was followed by her mother's.
Constand testified she had taken blue pills from Cosby, and when Constand's mother questioned Cosby about the pills, he said they were prescription pills. He said Constand never told him to stop and was conscious throughout. The interview was conducted about two weeks after Andrea Constand went to police. But, under cross-examination by Kathleen Bliss, an attorney for Mr. Cosby, Detective Reape said he had concluded that the varying times were not important. Her testimony prompted Cosby, sitting with his lawyers at the defense table, to open his eyes wide.
Cosby's first trial ended without a verdict.
On Monday, the defense tried to cast Constand as an opportunist who baited Cosby by feigning romantic interest in him. But Mesereau said phone records showed she did not make any phone calls to Cosby's Philadelphia phone number that month. Five of the women were called by the prosecution to testify and show an alleged pattern of criminal behavior by Cosby even though the statute of limitations have run out on filing criminal charges in their cases.
Constand, 45, left the witness stand Monday after testifying for seven hours over two days.
"I don't know what that means", Constand replied. Judge Steven T. O'Neill allowed certain evidence about the settlement to be used at retrial, but it was not used during the 2017 trial.
The Associated Press does not typically identify people who say they are victims of sexual assault unless they grant permission, which Constand and the other women have done.