Bleeding
Bleeding to death would include oxygen deprivation to the brain, which is a euphoric experience.
The folks who use inhalants as recreational drugs (glue sniffers, "huffers") do so because the solvents cause the blood vessels in the brain to dilate, then constrict in a rebound effect. That restriction leads to oxygen deprivation and euphoria.
(Oxygen deprivation is not, repeat not, the cause of right-wing conservatism as suspected by some. They are not euphoric. The origin of conservatism is thought by some faux scholars to be a stroke or some other blood supply problem near the center of their cognizance, such as hemorroids. ; )
Arf