and make her wear it. yes I agree with TG that comunicatin is key.
100%
Question how did you get her to let you tie her up? did she just do it becouse she knew it turned you on? or was she into it.

If she is into it. yes respect her limits but help her to expand her limits I still say go slow help her. Explore things that floats her boat then come back to yours.

If reading poatry in the park rocks her world. Then do it and I bet her limits will expand.

Show her erotic photo's of corseted women. Explore it with her be non threating. Explain to her what it is that turns you on. To a woman a corset probly looks like boxer shorts.