I remember Googling this awhile back ago. The percentage of women who are able to do this I think are about the same or smaller then women that squirt. As most women know the breasts can be a trigger or primer for the clitoris. With the right woman who are sensative there can drive the clitoris steering with the breasts to orgasm. My understanding is how to drive it there varues from woman to woman, ie nippl, e, cleavage, breast fucking, light or hard play. Usually takes some time and patience.
I know a civi woman I played with before she had extremely sensitive breasts. However by the time i knew about breast orgasms, she had a boon job, lost some sensitivity and is now engaged. However I admit we have fooled around twice during and I tried my damndest to make it work.
As far as guys getting stimulated. Stripper once opened my shirt (I wear dress shirts to SCs for this exact reason) and started playing with mine, then she started nibbling and sucking on them. I did not complain one bit. My experience is too many girls ignore the fact that as for as the nerves nipples are pretty similar to both men and women.
I also get eargasms from dirty talk combined with light kisses on and around my ears, and whole body orgasms when I get nibbled and kissed the back of my neck...mmmmmm! Love it!