" Oh, for crying out loud. This was like some kind of modern version of My Fair Lady.
Only with Vampyres.
She made herself breathe evenly for a few moments. "You've made your point."
"Have I? How fortuitous." As he lounged back in his chair, all the subtle signs of aggravation disappeared. "Then perhaps we should get back to the task at hand, so that I can determine what you have learned before going on to teach you what you haven't."
Okay, that went too far. One small part of her mind--the wary part, the sensible part -- started to whisper, "Don't say it, don't say it..."
But the rest of her was too exasperated to listen. She flung out her hands and opened her eyes wide. "Who says fortuitous these days?"
He just looked at her. The slanted angle of his mouth had returned, as well as the slight snap to his diction. "Apparently, I do. Now if you are quite through, it might behoove you to remember that a successful attendant is nowhere near this argumentative with her patron."
The devil took hold of her tongue. There was no other explanation for it.
"Behoove," she said.
The angle of his mouth leveled out, and his voice turned exceedingly, dangerously soft. "Yes. Behoove."
She opened her mouth. Shut it. Opened it again. "Don't say it."
Gray-green eyes narrowed, daring her to cross the line. "

― Thea Harrison , Night's Honor (Elder Races, #7)