Sex Cousin
Someone that's had sex with someone who's had sex with someone you have. Can be up to 4 times removed.
Girl 1: Me and Jenny are sex cousins.
Girl 2: How?
Girl 1: She had sex with John, who had sex with Sarah who had sex with Colin who had sex with me.
Girl 2: So 3 times removed then.
Girl 2: How?
Girl 1: She had sex with John, who had sex with Sarah who had sex with Colin who had sex with me.
Girl 2: So 3 times removed then.