A jerk fest. Developed from the phrase "Everytime you masturbate, God kills a kitten." Thus to masturbate many times within a night is to kill many kittens. Hence, "death to all kittens."
Buddy: This is some really hot porn.
Dude: Death to all kittens!
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