Edmund White, My Lives:
In those days, gay guys divided other gay men into three categories: forget-it; hot numbers; and sisters. A sister was a pal in whom there could never be any further sexual interest, even if the initial meeting had occurred through cruising. With a sister one let down one’s hair and relaxed. One no longer had to look good or appear desirable or (depending on the target audience) vaguely menacing. With a sister one could “dish,” that is, talk about real interests like dick size, one’s own humiliation in the bar last night, the fight to lose weight or the latest Streisand record. Presumably one was more honest with a “sister” than with a “husband,” though some gay men found campiness more a strain than dull normality. Sisterhood, after all, was a link to the queer past and required imagination and flair.