Ritual : shibari. Masters at Midnight novellas

High-powered executive Imogen prides herself on being an independent woman who doesn't need a man. She only yields when she's with Giles, a Masterful yet younger colleague who shares her taste for BDSM. He revels in watching her lose control during their games of domination and submission, while she enjoys his powerful nature and the edge of pain to heighten her pleasure. Imogen is satisfied with their secret arrangement until Giles asks her try shibari, a form of rope bondage-the ultimate ritual in submission and display of trust.
His request pushes Imogen beyond her comfort zone, forcing her to explore her boundaries and her relationship with Giles. He's already her Master at Midnight, when she allows it. But can she let herself take their bond to the next level?