The more I think about it, I am thinking that exsanguinate was meant as a gruesome form of (find spring). I believe that the elf-blood recovery thing was an after thought. Developining the exsanguinate thing even further, I'd like to suggest that orcs can do blood rituals.

By slathering themselves with different types of blood, the orcs can evoke effects.

Example of effects:
1. a swarm of blood flies:
The flies bite everyone in the vicinity of the orcs. They are attracted by the blood slathered on the orcs. They cause people to come out of hiding, (twitching, scratching, itching, etc).

2. gagging stench
when someone talks or yells, they have a chance of taking a hit to moralle. Basically, they inhale the awful smell of the orc.

3. toughened skin.
Giant blood might burn and turn orc skin to tough leather, kind of like bark skin.