This is super interesting! I've not tried it, but I can see how it would have a lot of potential to help some women. My last birth was a UC(planning another with current bun in the oven), and I had a hospital birth before that. Laura Shanley's info is very much about the connection between sex and birth. That they come out much the way they went in.
Erotic movement, stimulation, intimacy... All of these things helped promote a more peaceful natural labor. I was pretty shy last time, and ended up birthing almost entirely by myself, but I can see how interacting with my DH or channeling my own sexual energy would help.
Interestingly, while pushing out my daughter, I felt that getting into the exact position in which I typically reach orgasm and using the same movement was what it took it birth her. I tried the whole squatting thing, but ended up on my knees with my hips thrust forward, my legs close together. Excuse me if that is TMI.
A little background... I could never achieve O from intercourse prior to having met DH. I "learned" how to with him, and had a limited range in which it would happen at the time of my daughter's birth. I am curious to see, years later after having expanded my O repertoire, if I am able to birth in a different position, and if it will match the position I was when I got pregnant(I can recall the exact "oopsy" responsible). Watching UC birth videos, I think this could be true... The connection between "out the same way they went in". Birth connected to "the little death". I see women get into positions that are inherently sexual. I think attended births, where women are encouraged/coached into positions they might not choose, might not have the same story. I think of hospital births where women are stuck on their backs with their feet in the air(where I have been before), and I can see how that wouldn't facilitate gentle birth for many woman. I reach O most often on top.
Back on topic... I think clitoral stimulation would be something to try!