The blood on you'r knuckles/fist after fisting a woman while she is in her period. It is also possible to recieve bloody whale knuckles when you fist a man in the anus, popping his cherry. Well associated with the Duluth Corsage.
Oh Man! I fisted Melinda last night, she was in her period, but I didnt care, and boy did i have some serious bloody whale knuckles! What a mess!