The 79-year-old Cosby is charged with drugging and violating Constand at his suburban Philadelphia home in 2004. In 2005, after the assault and a failed criminal investigation, she filed a civil lawsuit against Cosby and settled.
"Once you got hold of your phone records and realized you can not have been passed out ... the night you told police - you changed your story?" defense attorney Angela Agrusa asked.
Agrusa contended that, after poring over her phone records, Constand realized she'd placed almost 10 calls to various friends the night of March 16.
Constand, who returns to the witness stand Wednesday, described how her professional relationship with the Temple University trustee evolved into a friendship that she considered critical to the school's athletics department where she worked. Constand said the calls mostly concerned the women's basketball team.
Bill Cosby arrived for the third day of his sexual assault trial accompanied by one of his co-stars from his 1970s movie run. She initially told officers she had never been alone with Cosby before the night of the incident and that she had largely cut off contact with him afterward, neither of which was true.
The defense repeatedly pointed out that during the night of the alleged sexual assault, a fire had been lit, the lights were dimmed and incense provided by Constand burned, all contributing to a romantic mood.
"He was sorry that you were upset", defense lawyer Angela Agrusa said, providing an alternate explanation for Cosby's apology.
"I trusted him. I wasn't scared of him in any way", said Constand. "I wanted it to stop".
"Eventually, he asked me to come up to his house to talk about basketball", she continued, noting that she also gave him her personal phone number.
Constand is one of around 60 women who have accused Cosby of sexually violating them but the prosecution has gone ahead on just Constand's allegations due to the statute of limitations passing for almost every other of those claims.
Cosby has faced allegations of sexual assault from dozens of women, though Constand's accusation is the only one to lead to criminal charges. "I remember him being behind me, making those grunting sounds", she testified.
Constand, 44, said that Cosby then proceeded to digitally penetrate her and forced her to give him a hand job. Cosby is one of Temple's most famous alumni and a big supporter of the team. Constand went on to admit she spoke to Cosby the morning after the alleged attack, something she had previously hidden from police, and kept in touch with the actor because she was afraid of how the incident would affect her life and career. Mr Cosby says he gave the woman Benadryl to relieve stress and insists their sexual relations were consensual. She alleged that after several minutes of talking, she began to slur her words and told Cosby she had trouble seeing him.
Ms Johnson said she held Mr Cosby in the "highest regard and esteem" until he invited her for lunch and insisted she take a pill to "relax". "My mouth was very cottony".
"I felt his hand inside my vagina, moving in and out". Some time later, she says, she woke up half-naked in the bed in his hotel room. She testified that's when Cosby assaulted her. "A mentor", she said. "And so, I just went along with it".