2 girls who bang their hips and pubic bones against each other as they make love to each other.
Oh my! Did you see those flatcockers in action?
I live in the South and this word has been in use for many years here. I was surprised it is not currently featured at urbandictionary.com.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi