I've never read, let alone written, fic for this pairing before but here goes.

"Ruby. Our town's sheriff may not concern herself too much with traffic laws, but I intend to protect the safety of Storybrooke. Please move your car out of the no-parking zone."

Ruby, sitting in her cherry-red convertible, stuck her head out over the driver-side door to look at the lines painted on the grocery store parking lot.

"I'm maybe an inch over the line!" she protested, exaspiration in her voice. "Maybe!"

Madame Mayor folded her arms. "Well I'd maybe like to see you tell that to a traffic court judge when you maybe face a significant fine." Her voice was cold, mocking.

Ruby fumed, and decided she'd had enough. She knew provoking the mayor might not be the smartest decision but she'd had a hell of a day and this had been the last straw.

Ruby hopped out of her car and rounded the hood to confront the mayor directly. She faced the formidable figure square-on with her hands on her hips.

"Look, I don't know what got that stick wedged so firmly up your ass but you need to remember that though you may be mayor you're not the fucking queen. You can't honestly expect everyone to bow when you walk by. I don't know what your big issue with my parking is, but you need to get over it and just go buy your fucking groceries."

The parking lot was largely empty, but the altercation had caught the notice of the sheriff who was ready to jump in should the altercation escalate to violence, which it looked like it might.

Regina took a step closer to Ruby, who stepped back and found her legs pressing against her bumper.

"Just who do you think you are, talking to me like that?" Regina's tone was icy yet burned with indignant anger. "Profanities are for simpleminded people who lack the vocabulary to eloquently and satisfactorily speak their mind. Which you aren't, are you?"

Ruby was admittedly a bit intimidated by the sinister teasing smile, but held her ground. "Why use flowery language when one can effectively make her point very concisely and in a way anyone can comprehend?" she challenged.

Regina leaned in further, and Ruby worried about a dent in her hood as she fell back with a thump. The mayor placed a hand on either side of the young woman, who visibly gulped. Amusement flickered in dark eyes as a sinister smile formed.

Their bodies were millimeters from touching, and Ruby could feel her body react despite herself. There was something wildly erotic about the situation. She bit her lower lip, then ran her tongue over it, staring into the eyes of the most powerful woman in town.

Regina watched closely as Ruby reacted to the proximity and bore a twisted grin as she dipped her head.

Ruby suppressed a moan as she felt the mayor languidly run her tongue over a cherry-flavored lower lip. Her eyes slid shut with pleasure when Regina suddenly, gently, bit it. She felt her legs go weak, the weight of the mayor pinning her to the hood of the car, as the kiss was deepened.

In a squad car parked two rows away, Emma sat stunned.

"Well that went from zero to lesbian faster than I could take out my gaydar."