But Ms. Zaloom, who has taught high school students about sex for two decades, said she was grateful for the new standard, even as she acknowledged the students’ unease.

“What’s really important to know is that sex is not always super smooth,” she told her 10th graders. “It can be awkward, and that’s actually normal and shows things are O.K.”

The students did not seem convinced. They sat in groups to brainstorm ways to ask for affirmative consent. They crossed off a list of options: “Can I touch you there?” Too clinical. “Do you want to do this?” Too tentative. “Do you like that?” Not direct enough.

“They’re all really awkward and bizarre,” one girl said.

“Did you come up with any on your own?” Ms. Zaloom asked.

One boy offered up two words: “You good?”

That drew nearly unanimous nods of approval.

Under the new law, high school students in California must be educated about the concept of affirmative consent — but they are not actually being held to that standard. So a high school student on trial on rape charges would not have to prove that he or she obtained oral assent from the accuser. That was the case with a senior at the elite St. Paul’s School in New Hampshire this year who was accused of raping a freshman. The senior was acquitted of aggravated sexual assault but found guilty of statutory rape — sex with a minor.

As for college students, the law passed last year in California does not change the way sexual assault cases are prosecuted in criminal courts, only in the way they are handled by colleges, which are permitted to use affirmative consent as a standard.

Last year, Corey Mock, a student at the University of Tennessee-Chattanooga, was expelled after officials there found him guilty of sexual misconduct because he could not prove he had obtained verbal consent from a woman who accused him of sexual assault. But a Davidson County Chancery Court judge ruled in August that the university had “improperly shifted the burden of proof and imposed an untenable standard upon Mr. Mock to disprove the accusation.” The judge called the university’s ruling “arbitrary and capricious.”