The Black Door (The Black Door #1)
Velvet

Once a tiger in the sheets, his interest has cooled considerably, and she's wound so tight she's about to explode. But when a hot young escort introduces her to The Black Door and her best friend encourages her to try it out, she finds a fantasy playground for women - full of every sexual temptation a girl could dream of.
It is there that she meets a man who turns her out physically, mentally and emotionally. But when her sexual fantasy life starts to spill into her real life, everything starts to spiral out of control. She stands to lose everything that means something to her for that next, sweet fix.