A very sick sexual act. Why some find this stimulating i'll never know.
When the woman is having her menstrual peiod, the man gives oral sex and wipes his face sideways across the vagina several times. Having a blood-stained "smile" on his face he looks up to her and says "Why so serious?".
1: i did the joker to my girlfriend last night.
2: Dude, why do you always tell me this shit!?