Buttsax, also known as "Anal Sex," is when a man takes his penis, places it into his sex partners anus, then thrusts his pelvis forward and back, giving them both pleasure.
Billy : Mmm, you like that butt sax dont you Mrs. Jenkins
Mrs. Jenkins : Oh yes, so hard.
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