I don't think there would be a problem so long as
a. you and your woman came up with a story for your meeting should something happen
b. she knows CPR and how to handle herself in a crisis
c. preferably someone who is going to keep an eye on you during playtime and stop to ask if you need a breather. Slow and steady can be a lot better in the end than a bunch of wham-bam-crazy heart rhythmic sexiness.
d. you put a codicil to your will including your ATF if end up dying in her arms and she did everything she could to prevent that. (hey! That's traumatic stuff! I'd need some serious bereavement leave if that happened!)