1. The YUMMY act of draining blood either by wrist, neck, or other veiny part of the body. Any sharp blade will open you up nicely. Also a helpful medical tip from the Dark Ages!
2. The ancient Medieval art of draining all of the bad blood from the body and regenerating new better blood!

v. the act of drinking another's blood

Bloodletting of the penis, this involves it to soak and dry on a piece of paper to then be smoked. This is called penis blood cigarettes.