Stands for Lesbian Sex Cult. Basically, a gang or club made up of lesbians and bisexual girls who want to stand out. The ring leader or "lsc master" is normally a perverted guy, but can often be another female.
Male: Hey check out those babes!
Male2: Forget it man, they're the lsc.
Male: But we can still spy for some hott action
Male2: True. You get the cameraphone!