I'm a great believer in the test it on myself first method. Then if as you say I don't have the bits that she does, the go very slowly method seems to work.

And failing that, communicating all the time checking to see if she's ok. There is nothing wrong with a plan B if plan A turns out to be not such a good idea. I also think because of the nature of our lifestyle/play sometimes hurting someone physically (more than is pleasureable) is unavoidable. Especially if you are experimenting with new unexplored territory. Also you must trust that your sub will use her/his safeword in that case.