A Plano, Texas high school teacher has been arrested after a Snapchat flirtation with a 16-year-old boy led to beer pong, nude selfies, al fresco sex and the cancellation of her wedding, police say.

Alaina Danielle Ferguson, 23, was working as an algebra teacher at Plano Senior High School when the illicit relationship began, according to arrest affidavits.

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Ferguson allegedly contacted him after he left his Snapchat username on a test paper, Fox 4 reported.

That happened September, just after the beginning of the school year, and quickly led to the pair having sex on a park bench in Lewisville, the arrest affidavit said.

The pair continued their illicit affair both on and off-line, with Ferguson sending nude selfies to the teen and providing the alcohol for games of beer pong that would turn into sex sessions, authorities say.

At one point she allegedly had sex with him in her McKinney apartment while her fiancé was out of town.

The pair had sex 'several' more times in the apartment, police said.

Ferguson 'knew it was not the right thing to do, but it felt right at the time,' according to the officer who wrote the arrest warrant.

He added that 'she was going to break it off with her fiancé because she didn’t feel anything with him.'

Ferguson quit the school in October, but had sex with the teen at least one more time, in November, in the back of the teen's pickup after a football game, police said.

But the teen kept talking about it after she left - and it looks like that might have given the pair away.

'I heard the kid was just talking about it to his friends and I guess a teacher or a student over heard it,' Plano Senior High Student, Andy Flores told CBS.

'She’s kind of good looking… so she’s attractive,' he added.

Flores has been released on $100,000 bond and must wear an electronic monitoring device, deactivate all of her social media accounts and stop using the web.

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