Take away her hands, and you damn well better make her feel secure about her trust in you.
In my experience, women are more afraid to be tied up than give you nearly anything else.
Tying her up the first time was a bigger internal hurdle for her than the first time she gave me anal.
Even gave me sex, for the first time.
The absolute submission and trust involved in this act.
If she gives it, you better not fuck it up.