At the Mercy of Her Pleasure by Kayelle Allen

To free his enslaved brother from a cruel master, Senth, an all-party-fun-and-games thief, must take on the hardest assignment of his life: stealing from the Empress. To make matters worse, he has no choice but to work with NarrAy, a by-the-book rebel female captain whose addictive pheromones could jeopardize the mission and destroy Senth’s will.
When the unthinkable happens and NarrAy professes her love for him, Senth must decide if what he feels is real. Can he trust this woman? If he loves her back, can he still save his brother? Or will Senth end up at the mercy of her pleasure forever…