Eterra's Blessing

Quick question on Eterra’s Blessing. So, in a couple hours I will be rolling a Thorn Totem Shaman. I know Eterra’s Blessing is a skill I am supposed to use according to the guides. My concern is the targeting. In the crazy thick of a battle with effects going off and enemies everywhere I foresee that being an issue with my being able to pick a target out. If I do not target anything at all and just press the Eterra skill key will I be healed if I do not target myself?

If you cast it by passive - It will target your COMPANION or allie with lowest life.
If you cast by Thorn Shield, It 'll target who you cast thorn shield.

If you self-cast , will target who is NEAR YOUR PONITER (mouse)

Exemple:

You ______X ___________________ Bear

If X is your cursor form your mouse, Eterrra will target you.