Konnitch by Julie K. Cohen

Of all the times for his mating heat to strike… right in the middle of an op with a feisty female.

Konnitch
Konnitch needs a decoy for a dangerous op on Earth. The only qualified human is smart, fast, and too independent for her own good. Worse…. she sparks his mating heat. Just having her near drives him crazy, and now he can’t think about anything beyond bedding her. Even though he’s never burned so hot for a female, he won’t be able to hold out for long. When the op goes up in flames, forcing them together longer than he can handle, he will mate her…

Kaci
Kaci needs money, fast. Working for aliens is an act of desperation, but when an alien marshal with red skin, deadly horns, and tribal tattoos on a deliciously muscular chest offers her a deal, she jumps on it. Though she’d rather jump him. The way he looks at her makes her shiver… in a good way, but Kaci has no plans to become his plaything. When he goes into heat, what is she willing to do to complete her end of the deal?