Crimson Chin

A very difficult maneuver requiring the participant to go through the motions of eating a girl out but with your chin. This term is most commonly referred to as chinning or chin. The crimson chin is when one chins a girl who is on her period causing the blood to be stained on the chin, leaving a crimson hue on the chin, dubbing the crimson chin.

Yo dude you can still see my crimson chin from last night