The two grew so close that they began texting one another. The texts began innocently, but each said the other eventually began sending messages that were flirtatious and suggestive.
"She just like kind of gets more into the texts, like they're starting to get dirtier and dirtier," Bubba said.
Lusk, meanwhile, said Bubba sent her a message saying he wanted to see her without her clothes on.
"I'm like, 'Oh come on.' I said, 'You'd have nightmares.' I mean, I would laugh it off," she said. "Then he said, 'Oh well, I bet you do things to yourself when you're by yourself.'"
Even those texts, she said, didn't prepare her for one she received while working at her store.
"I was at work one day and he said, 'If I came down to your shop, would you give me oral sex?' And I was stunned," Lusk said. "I'm embarrassed to say this, but I texted back, 'WTF,' and he's like, 'Oh well, I'm just joking.'"
"I think I didn't want to hurt him," she added, "which seems a little ridiculous."
Lusk eventually sent Bubba a picture of herself wearing only a bra.
But her feelings toward Bubba, she insisted, weren't amorous.
"There were times when he would say that, 'Oh, you look great. You look hot.' And I would just laugh and go, 'Whatever, I don't think so.' And I'm sure that there was something in there that was kind of nice to hear. But it wasn't amorous," she said.
In the spring of 2010, the text messages suddenly turned into something more tangible. With his friends egging him on, Bubba set out to make Lusk his first conquest, and around lunchtime one April day, he visited the Lusk's home.
Construction was going on at the house at the time, and Lusk said that when Bubba arrived she had the sense he wanted to speak with her privately. She led him to her daughter's bedroom.
Lusk said Bubba seemed nervous. She put her hand on his shoulder and asked what was going on.
"And then I kind of gave him a hug, thinking he just needed a hug," she said, "and then he took his pants down."
Lusk said she was shocked and struggled to explain what happened next.
"I just froze," she said. "I don't even know -- I didn't look down -- that I even touched him. But I probably did."
Under questioning by detectives, Lusk admitted to touching Bubba's penis.
Lusk told "20/20" that she then immediately left the room, took a deep breath and then came back in, telling Bubba he needed to return to school.
But according to Bubba, his interaction with Lusk went much further than that.
"We just had oral sex and that's basically all," he told "20/20."
"She just said if I was sure if I wanted to go along with it. And I said yeah," Bubba said.
Later, he said, Lusk told him that "next time I'd have a chance to please her."
Bubba said he didn't want to report the incident to the police, but he bragged to his friends. Rumors ricocheted around the small town and around the high school attended by Lusk's daughter, Karlie, and where her husband, Kevin, served as principal.
Lusk said she talked to them both about what happened -- and both decided to stand by her.
"She's not completely innocent, but she's not horrible," said Karlie Lusk. "She's also a victim, too. She was taken advantage of when she was very vulnerable and upset and sad."
Kevin Lusk said his wife "made some unbelievably stupid decisions," but he believed her when she told him that no oral sex had taken place between her and Bubba.
"I love my wife. I believe her. I support her," Kevin Lusk told "20/20."
At Kevin Lusk's urging, Linda Lusk called Heidi Frank, Bubba's mother, and told her what happened. She also gave a statement to police.
In June, prosecutors announced they were charging Lusk with third-degree child molestation, a felony.
Lusk continued to deny Bubba's oral sex allegation and took a polygraph test to support her defense. A polygraph examiner found no evidence of deception in her answers.
A psychological report provided to "20/20" determined Lusk was not a predator but, rather, "crossed over appropriate boundaries in this specific relationship."
Such a boundary would never have been crossed, said Karlie Lusk, if her mother hadn't been grieving over Taylor's death.
"If she hadn't suffered the loss from Taylor and if she hadn't been where she was," Karlie said, "I'm positive this wouldn't have happened."
Kevin Lusk said he regrets that his wife didn't seek help after Taylor's death.
"You need to get it handled. You need to go talk to somebody. We didn't," he said.
Prosecutors pushed on with their case. Under threat of an even harsher charge of child rape, Lusk ultimately decided to provide an Alford plea -- a plea in which a defendant maintains she did not commit a crime but admits prosecutors have enough information to convict her.
Lusk was sentenced to 90 days in prison with daytime work release, allowing her to continue working at her store but forcing her to sleep in jail.
"You were strip-searched every night," she said. "That's so humiliating."
She also had to register as a sex offender -- watch video here -- a designation that would prohibit Lusk from having contact with children other than her own. Lusk will be considered a sex offender for 10 years.
"It's devastating, because I'm the kind of person that's always taking care of kids," she said. "So then to be told that I can't be around children -- it's just kind of hard to wrap your brain around it."
Earlier this week, the restrictions placed on Lusk may have proven too great for her to bear: She was arrested on a charge of a parole violation for crossing a county line without telling her parole officer to attend her daughter's swim meet.
A hearing on the charge is scheduled to take place on Nov. 21. For now, Lusk is back in jail, this time without work release, waiting for her day in court.
Bubba Frank, meanwhile, says he is having a tough time moving on from the scandal, which rocked his high school.
"I see how hard it is for him to deal with this at school," said Heidi Frank. "He should be able to go to school and not have to worry about something like this. ... I have to see that as a mom, and it kills me."