Full: For 20...39...44 seconds, you gain +2 Blood Magic and +2 Curses, but whenever you sacrifice Health, you sacrifice 50% more than the normal amount.
Concise: (20...39...44 seconds.) You have +2 Blood Magic and Curses. Sacrifice 50% more Health than normal.
It is possible to have no skills that sacrifice, so you can use it with no down side.
The +2 Blood Magic is not applied to the spell for the initial cast; the +2 is applied after the casting.
With 11 points in blood magic and an enchantment duration +20% weapon, Awaken the Blood can be kept on continuously, even before the +2 blood magic that is added on for the second cast.