She and another accuser delivered gripping testimony this week, but so far, jurors have only heard Cosby through a phone call Constand's mother recorded and transcripts of a police interview and his deposition in a 2005 lawsuit.
"Quaaludes happen to be the drug that kids, young people were using to party with and there were times when I wanted to have them just in case", Cosby said.
"If it's a well-known person, the victim takes on a lot of responsibility for that person's reputation, especially if that person is well-liked or beloved", Veronique Valliere testified.
Constand testified earlier this week that the pills, which prosecutors have suggested might not have been Benadryl, left her incapacitated at his Philadelphia-area home before Cosby sexually assaulted her.
This psychological analysis boosted the prosecution's case by explaining Constand's behavior and assuring the jury that alleged inconsistencies in her testimony aren't reason to discredit the entire account.
On Thursday, jurors heard excerpts from the comedian's lurid, decade-old deposition, but explosive sections about him obtaining quaaludes and giving them to women before sex are yet to come. It's unclear whether Cosby's compromised vision allows him to see either the audience or the jury, but his movements were noticeable, even more so than this morning when a detective read portions of a statement that seemed to have made him uncomfortable.
Montgomery County Det. James Reape read aloud from the deposition Cosby provided to authorities in 2005 in court on Friday. It's unclear if he will take the witness stand.
The outcome of his trial in the Philadelphia suburb of Norristown, Pa., largely hinges on whether jurors believe Ms. Constand's testimony, which came on the trial's second day.More news: Congressional Baseball Practice Shooter Acted Alone, No Ties to Terror Organization
"My dress was pulled up from the bottom, and it was pulled down from the top, and my breasts were out", she said, crying.
This was likely because the 79-year-old comedian's lawyers question why Constand kept calling Cosby after she says he drugged and sexually assaulted her, and why she waited a year to go to police with it. After "necking" on the couch, Cosby went to bed and Constand slept on the couch.
"Tell your mother you were awake, tell your mother about the orgasm, tell you mother we talked", he said he had wanted to plead.
Constand has said Cosby gave her pills he suggested were herbal, leaving her barely conscious and unable to resist his advances. The defense starts its case Monday.
In January 2004, Ms. Constand said, Mr. Cosby invited her to his house again to discuss her career options.
Constand's sexual orientation has not been mentioned during the trial.
Cosby recounted calling Constand's family and offering her money for graduate school. Cosby spokesman Andrew Wyatt said the TV star told her stay away so that she wouldn't have to endure the "media circus". Earlier in the week, Keshia Knight-Pulliam, who played the youngest daughter, Rudy, on "The Cosby Show, " attended in support of Cosby.
The Associated Press does not typically identify people who say they are victims of sexual assault unless they grant permission, which Constand has done.