She told the hearing she was "more than mildly" drunk at the dinner after drinking at a teacher's home prior to the event, but had previously told the CAC she was "somewhat intoxicated" and still able to hold a conversation.
According to an agreed statement of facts, the teacher left the dinner with the student to be driven home, but asked to stop a few blocks away to hide her address from students.
"It was one of the only sensible decisions I was making," the teacher said during cross-examination by CAC counsel Seamus Woods.
Woods asked if it was "just convenient" the teacher, with 12-and-a-half-years experience, couldn't remember then performing oral sex on the teen.
"I can't say it didn't [happen]," she said.
"[The student] says that it did," Woods retorted, to which the teacher replied: "I can't deny that, but he's also said a lot of things."
Word of the incident quickly spread through the school community, and Fraser's principal was alerted to the matter when another teacher overheard students discussing it.
Initially denying the accusations, the teacher said she "couldn't fathom" the scenario, but after hearing accounts of her behaviour during the dinner, accepted responsibility for the incident.
The teacher, who admitted her drinking problem began three years before the incident, said her actions had brought "an element of shame and embarrassment" to her family and former school.
"I'm a Jekyll and Hyde drinker," she told the hearing.
She said there were previous incidents in her past when she couldn't remember parts of an evening due to being too drunk.
However, Woods said the teacher had "exaggerated" alcohol as a factor in the incident.
"It is not plausible that the respondent doesn't remember it," he told the hearing.
"Although she does accept it may have in fact happened ... it is too convenient to be believed."
The teacher's counsel, Dizintra King, said her client's "blackout" and lack of recollection of events "has to be accepted as truth" because there was no evidence to suggest otherwise.
She said the student, in another situation involving an intoxicated woman, "might well have found himself looking at some sort of criminal charge".
Following the incident, the teacher resigned, said her marriage was failing, and had since sold her Hamilton home to move to another region.
She said she'd been sober since February 14, 2016, and attended alcohol rehab courses.
"I recognise my actions have caused huge rippling effects ... I want a new beginning. I know I'm good at teaching," she said.
She said she did not wish to further pursue a teaching career.
Tribunal chair Theo Baker, Simon Williams and Stuart King have reserved their decision.
