I have No. Idea. what she's talking about. The BDSM symbol is kind of like a yin yang but with a third division. Sort of like a cross between it and a triskelion. (http://en.wikipedia.org/wiki/BDSM_Emblem)

I can't say I've ever heard of there being a special lesbians-only one, though there's a hanky code for BDSM.