The Hinky Velvet Chair — Jennifer Stevenson

Fraud cop Jewel has too much of a good thing. A hot con artist is her new partner and a bossy demon is her new booty slave.
Today she's busting the Venus Machine, which makes a person irresistibly attractive. Jewel sits in the Venus Machine's velvet chair to prove it's a fountain of flimflam. She won't do that again in a hurry.
Her demon vanishes in the middle of the case. Her sneaky partner is hiding something, of course. And Jewel has to face down four con artists with the strongest weapon in her holster...her terrible reputation.