"Earning your red wings" is having sex with a woman while she is having her periods. I think it is an old Hells Angels thing. They also used to have others such as "Black wings" which can be either having oral sex with a black woman or having sex with a dead woman. And "Blue wings" which was having oral sex with a female police officer, usually against her will. And before someone asks, yes, I do have my "red wings"